OM 711-1 MicroTech II Vertical Self

OM 711-1 MicroTech II Vertical Self
Operation Manual
OM-711-1
Group: Applied Systems
Part Number: OM711-1
Date: June 2004
MicroTech II™
Vertical Self-Contained Unit Controller
Discharge Air Control (DAC)
•
© 2004 McQuay International
Used with McQuay models: SWP, SWT
Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Using the Keypad/Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Display Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Password Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Keypad Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Keypad/Display Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Keypad/Display Menu Reference . . . . . . . . . . . . . . . . . . . . . . . . . . 9
System Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Air/Water Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Schedules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Setup/Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Active Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Previous Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Operator’s Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Determining Unit Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
UnitStatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clg Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Htg Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clg Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Htg Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Auto/Manual Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ctrl Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appl Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Occupancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Occ Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Occ Src . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tenant Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Emergency Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Setting Controller Date and Time . . . . . . . . . . . . . . . . . . . . .
Internal Daily Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Holiday Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
One Event Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optimal Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Time Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . .
Network Time Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alarm Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
About Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote Alarm Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Local Alarm Indication (Keypad/Display) . . . . . . . . . . . . . . . .
Remote Alarm Clearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring Remote Alarm Output . . . . . . . . . . . . . . . . . . . .
Unit Configuration/Service Parameters . . . . . . . . . . . . . . . . . . . . .
Calibrate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Zone (Space) Temperature Sensor . . . . . . . . . . . . . . . . . . .
Miscellaneous Service Parameters . . . . . . . . . . . . . . . . . . . .
Control Timer Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual Output Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Startup Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Before Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Fan Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Heat/Cool Changeover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Outdoor Air Damper Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Economizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Economizer Changeover Method (Airside) . . . . . . . . . . . . . . 65
Economizer Changeover Method (Waterside) . . . . . . . . . . . . 65
Minimum Ventilation Control (Airside Economizer Only) . . . . 66
Cooling: Multistage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Low Ambient Cooling Lockout . . . . . . . . . . . . . . . . . . . . . . . . 71
Compressor Staging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Cooling: Modulating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Heating: Multistage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Discharge Air Low Limit Control . . . . . . . . . . . . . . . . . . . . . . . 74
Heating: Modulating Temperature Control . . . . . . . . . . . . . . . 74
Heating to Fan Only Operating State . . . . . . . . . . . . . . . . . . . 75
Morning Warm-up Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
High Ambient Heating Lockout . . . . . . . . . . . . . . . . . . . . . . . 75
Discharge Air Low Limit Control . . . . . . . . . . . . . . . . . . . . . . . 75
Discharge Setpoint Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Cooling Discharge Setpoint Reset . . . . . . . . . . . . . . . . . . . . . 76
Heating Discharge Setpoint Reset . . . . . . . . . . . . . . . . . . . . . 79
Discharge Fan Capacity Control . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Duct Static Pressure Control . . . . . . . . . . . . . . . . . . . . . . . . . 81
Discharge Fan Direct Position Control . . . . . . . . . . . . . . . . . . 82
Direct Building Static Pressure Control . . . . . . . . . . . . . . . . . 82
Post Heat Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Unoccupied Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Unoccupied Heating (Night Setback) . . . . . . . . . . . . . . . . . . . 83
Unoccupied Cooling (Night Setup) . . . . . . . . . . . . . . . . . . . . . 83
Purge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Alarm Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Lo Disch Tmp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
38
38
38
38
38
38
39
40
40
40
41
41
42
43
43
44
44
44
44
45
45
46
46
46
46
48
48
49
51
51
51
52
52
53
55
MicroTech II DDC Features . . . . . . . . . . . . . . . . . . . . . . . 90
Direct PID Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Cascaded PID Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
PID Control Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Proportional Band and Integral Time . . . . . . . . . . . . . . . . . . . 91
Adjusting PID Control Parameters . . . . . . . . . . . . . . . . . . . . . . . . . 91
Correcting System Instability (“Hunting”) . . . . . . . . . . . . . . . . 91
Correcting System “Sluggishness” . . . . . . . . . . . . . . . . . . . . . 92
PRAC Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Description of Operation . . . . . . . . . . . . . . . . . . . . . . . . . 57
Software Identification and Configuration . . . . . . . . 93
Operating States and Sequences . . . . . . . . . . . . . . . . . . . . . . . . .
About Operating States . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating State Descriptions . . . . . . . . . . . . . . . . . . . . . . . .
Operating State Sequence Chart . . . . . . . . . . . . . . . . . . . . .
57
57
58
60
Software Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Identifying Application Code Using Unit Keypad/Display . . . . 93
Main Control Board (MCB) Configuration . . . . . . . . . . . . . . . 93
Main Control Board (MCB) Data Archiving . . . . . . . . . . . . . . 94
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
McQuay and MicroTech II are registered trademarks of McQuay International.
Microsoft is a registered trademark of Microsoft Corporation.
Windows is a trademark of Microsoft Corporation.
Copyright © 2004 McQuay International. All rights reserved throughout the world.
Introduction
model-specific installation and maintenance manual (see
Table 1).
This manual provides information regarding the MicroTech
II control system used in the McQuay Vertical
Self-Contained unit product line. It specifically describes the
sequences of operation and programmable options for units
with factory equipped discharge air control (DAC) software.
It also includes information regarding how to use the
keypad/display to enter and display data.
Table 1: Model-specific vertical self-contained unit
installation literature
Self-Contained unit model
Installation & maintenance
data bulletin number
SWP (18-105 tons)
IM 708-1
SWT (18-105 tons)
IM 709-1
For information regarding MicroTech II components,
input/output configurations, field wiring options and
requirements, and service procedures, refer to IM710-1,
MicroTech II Vertical Self-Contained Unit Controller. For
installation and startup instructions and general information
regarding a particular rooftop unit, refer to the applicable
NOTICE
This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with
this instruction manual, may cause interference to radio communications. It has been tested and found to comply with the
limits for a Class A digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide reasonable
protection against detrimental interference when the equipment is operated in a commercial environment. Operation of this
equipment in a residential area is likely to cause detrimental interference in which case users are required to correct the
interference at their own expense. McQuay International disclaims any liability resulting from any interference or for
the correction thereof.
WARNING
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech II control panel must be performed
only by personnel that are knowledgeable in the operation of the equipment being controlled.
CAUTION
Extreme temperature can damage system components.
The MicroTech II controller is designed to operate in ambient temperatures from -20°F to 125°F. It can be stored in ambient
temperatures from -40°F to 140°F. It is designed to be stored and operated in relative humidity up to 95% (non-condensing).
CAUTION
Static sensitive components. A static discharge while handling electronic circuit boards can damage components.
Discharge any static electrical charge by touching the bare metal inside the main control panel before performing any service
work. Never unplug any cables, circuit board terminal blocks, relay modules, or power plugs while power is applied to the
panel.
McQuay OM-711-1
1
Getting Started
The MicroTech II Vertical Self-Contained Unit Controller is
a self-contained device capable of complete, stand-alone
operation. Information in the controller can be displayed and
modified by using the keypad/display in the unit main
control panel.
notation [8=1 or 2]. This notation means that the Duct
Pressure menu (and all its menu items) applies to the specific
unit only if the eighth position in its Software Configuration
Code is a 1 or a 2. Otherwise, the menu or menu item is not
applicable to the unit and does not affect its operation.
The following sections describe how to use the
keypad/display.
Figure 1: Keypad/display
Using the Keypad/Display
The keypad/display, shown in Figure 1, is provided with all
MicroTech II Vertical Self-Contained Unit Controllers on
these units. With the keypad/display, operating conditions,
system alarms, control parameters, and schedules can be
monitored. After password entry, setpoints, parameters, and
schedules can be edited.
Discharge Cooling
Disch Air= 55.0°F
Clg Capacity= 50%
Eff Clg Spt= 55°F
Menu Structure
The keypad accessible information in the MicroTech II
controller is organized in a menu structure to provide quick
access. As shown in Figure 2 on page 3, this structure
contains one main menu and a string of 54 submenus. Each
submenu is made up of one or more menu items. The string
of 54 submenus is divided into eight categories. The main
menu has eight items within it that point or provide a
bookmark to the first submenu within the respective
category. The eight categories in the main menu are System
Summary, Air/Water Flow, Temperature, Humidity,
Schedules, Setup/Service, Active Alarms, and Previous
Alarms. The name of each category generally describes the
basic purpose of the menus in the particular group. Complete
information regarding the contents of each submenu is
included in “Keypad/Display Menu Reference” on page 9.
Note: Only those menus applicable to units with a 0 or 2 in
the first position of the Software Configuration Code
are described in this manual. Refer to OM 712 for all
others.
A number of menus and menu items that appear on the unit
keypad/display are conditional and, depending on the unit
software configuration, may not apply to a specific unit.
The unit software configuration is defined by a Software
Configuration Code shown on a label located on the
backside of the door where the keypad/display is mounted.
The Software Configuration Code also can be displayed via
the four menu items in the Configuration Code menu on the
unit keypad\display (see “Software Identification and
Configuration” on page 93).
The menus and menu items that are shaded in Figure 2 are
conditional. Each conditional menu or menu item in Figure 2
includes a reference to the position in the Software
Configuration Code upon which its applicability depends.
For example, the Duct Pressure menu in Figure 2 includes a
2
McQuay OM-711-1
McQuay OM-711-1
CANCEL
BACK
Sub Menus
8
OccSrc= _____
Tnt Ovrd= 0 min
Emerg Override= Norm
Htg Capacity= xxx%
Clg Status= _____
Htg Status= _____
BSP Db= 0.010"WC
BldgSP Spt= 0.050"WC
Bldg Press= x.xxx"WC
Bldg Pressure
[8=1 or 2]
Control Temp= xxx.x°F
Htg Capacity= xxx%
Eff Htg Spt= xxx.x°F
Occ Htg Spt= 70.0°F
Htg Deadband= 2.0°F
CtrlTemp Src= Return
Space Temp= xxx.x°F
UnoccHtg Spt= 55.0°F
UnoccHtgDiff= 3.0°F
Htg Status= _____
OATHtg Lock= 55°F
OATLock Diff= 1°F
Control Temp= xxx.x°F
Clg Capacity= xxx%
Eff Clg Spt= xxx.x°F
Occ Clg Spt= 75.0°F
Clg Deadband= 2.0°F
CtrlTemp Src= Return
Space Temp= xxx.x°F
UnoccClg Spt= 85.0°F
UnoccClgDiff= 3.0°F
Clg Status= _____
Min EWT= 55.0°F
Min EWT Diff= 3.0°F
OATLock Diff= 1°F
OATClg Lock= 55°F
Zone Heating
LWT= xxx.x°F
EWT= xxx.x°F
MAT= xxx.x°F
OA Temp= xxx.x°F
Disch Air= xxx.x°F
Return Air= xxx.x°F
[1=0 or 1]
Space Temp= xxx.x°F
Control Temp= xxx.x°F
Temperatures
Zone Cooling
Temperature
Occ Mode= Auto
Clg Capacity= xxx%
3
Occupancy= _____
UnitStatus= _____
Appl Mode= Heat/Cool
VAV Output= _____
[8=1 or 2]
Outdr Damper= _____
SAVE
Max Clg Spt= 65.0°F
Clg Reset= Airflow
[1=1 or 3]
Min Clg Spt@= 0
[1=1 or 3]
Max Clg Spt@= 100
[1=1 or 3]
Min Clg Spt= 55.0°F
Eff Clg Spt= xxx.x°F
DAT Clg Spt= 55.0°F
[1=1 or 3]
Clg Db= 2.0°F
Clg Capacity= xxx%
Disch Air= xxx.x°F
Discharge Cooling
Water Flow= _____
Water Flow Summary
[5=0]
2 Air/Water Flow
Select Menu
Save Edited Parameter
ENTER
BACK
Move Display Right
Move Edit Cursor Right
CANCEL
Backup To Previous Menu
Cancel Editing Command
Occupancy
Ctrl Mode= Off
Keypad Key Definitions
Move Display Left
Move Edit Cursor Left
System
1 System Summary
7
Active Alarms
Previous Alarms
6
4
Humidity
5
3
Temperature
Schedules
2
Air/Water Flow
Setup/Service
1
System Summary
Main Menu
EWT Diff= 3°F
EWT= xxx.x°F
Econo Pos= xxx%
Disch Air T= xxx.x°F
Waterside Econo
[4=1]
Setpoint= 160psi
Head P Cmp2= xxxpsi
Head P Cmp1= xxxpsi
Head Pressure
[5=1]
OA Damper Pos= xxx%
[4=0]
Eff Min OA Pos= xxx%
[4=0]
OA Ambient= _____
[4=0]
MinOA Pos= 10%
[4=0]
EconChgovr= Dry Bulb
[4=0]
EconChgovrT= 60°F
[4=0]
EconChgovrDiff= 1°F
[4=0]
Max Purge= 60 min
[4=0]
OA Temp= xxx.x°F
Airside Econo
Max Htg Spt= 120°F
Htg Reset= None
[1=1 or 3]
Min Htg Spt@= 0
[1=1 or 3]
Max Htg Spt@= 100
[1=1 or 3]
Min DAT Ctrl= Yes
MinDAT Limit= 55.0°F
[1=0 or 2]
Min Htg Spt= 60°F
Eff Htg Spt= xxx.x°F
DAT Htg Spt= 100.0°F
[1=1 or 3]
Htg Db= 2.0°F
Htg Capacity= xxx%
Disch Air= xxx.x°F
Discharge Heating
Disch Fan Cap= xxx%
DSP Db= 0.08"WC
DuctSP Spt= 1.00"WC
Duct Press= x.xx"WC
Duct Pressure
[8=1 or 2]
Clear Active Alarm
CLEAR
ALARM
Move Display Down
Decrement Adjustable Parameter
Fan Operation= _____
Disch Fan= _____
Flow Status= _____
Airflow Summary
Display Active Alarm
ALARM
Move Display Up
Increment Adjustable Parameter
A
Figure 2: Keypad accessible menu structure
3
A
Sub Menus (Continued)
4
4 Humidity
End= mmm dd@hh:mm
Tue= 00:00 - 00:00
Clg Propbd= 8.0°F
Htg Propbd= 12.0°F
ClgIntTime= 700 sec
WRV Propbd= 4.0psi
WRV IntTime= 10 sec
WRV Period= 10 sec
Period= 60 sec
HtgIntTime= 500 sec
Spt Source= Keypad
WRV DB= 10.0psi
PRAC= No
Zone Temp Setup
[1=0 or 2]
Head Pressure Setup
[5=1]
Stage Time= 5 min
Compressor 2= Enabled
Compressor 3= Enabled
[3=1-5]
Compressor 4= Enabled
[3=2-5]
Compressor 5= Enabled
[3=3]
Compressor 6= Enabled
[3=3]
Clg Method= Average
Compressor 1= Enabled
Compressor Setup
[2=1]
Comp 6= xxxxx hr [3=3]
Heating Op= xxxxx hr
[6>0]
Econo Op= xxxxx hr
[4=0or1]
Tnt Ovrd= xxxxx hr
Dehum Op= xxxxx hr
[1=0or2]
Comp 5= xxxxx hr [3=3]
Comp 4= xxxxx hr [3=2-5]
Comp 3= xxxxx hr [3=1-5]
Comp 2= xxxxx hr [2=1]
Pos # 13-15= x.xx
Mech Cool= xxxxx hr [2>0]
Disch Fan= xxxxx hr
Comp 1= xxxxx hr [2=1]
Clear Alarm= No
Pos # 5-8= x.xxx
Pos # 9-12= x.xxx
Timeout= 15 min
Pos # 1-4= x.xxx
Stage Time= 5 min
PRAC= No
Clg Period= 30 sec
ClgIntTime= 60 sec
Clg Propbd= 30°F
Chilled Water Setup
[2=2]
Airflow= 120 sec
LPAlm Delay= 45 sec
[2=1]
Comp Delay= 100 sec
[5=1]
Start Init= 180 sec
Post Heat= 0 min
[8=1 or 2]
Bypass Vlv= 300 sec
Service= 0 min
Recirculate= 3 min
[1=0 or 1]
Low DAT= 2 min
Max MWU= 90 min
[1=0 or 1]
Tnt Ovrd= 120 min
Timer Settings
PRAC= No
Clg Period= 30 sec
Clg IntTime= 60 sec
Clg Propbd= 30°F
Economizer Setup
[4=0or1]
Date= dd-mmm-yyyy
Day= day
Time= hh:mm:ss
Time/Date
Clg Zero OAT= 100°F
Hol 15=mmmdd-mmmdd
Passwords
OAT Sensor= No
Clg OAT= 85°F
Hol 16=mmmdd-mmmdd
MAT Sensor= Yes
Clg Rate= 0.4°F/min
Hol 14=mmmdd-mmmdd
Hol= 00:00 - 00:00
BSP Period= 5 sec
PRAC= No
PRAC= No
Stage Time= 10 min
[6=1,2 or 3]
Htg Propbd= 20°F
[6=4]
Htg IntTime= 240 sec
[6=4]
Htg Period= 10 sec
[6=4]
PRAC= No
[6=4]
SensorLocatn= Return
Maximum Stages= 4
Minimum Stages= 2
Dehum Ctrl= Occupied
Dehum Setup
[1=0 or 2]
BSP IntTime= 10 sec
DSP Period= 10 sec
Heating Setup
[6>0]
BSP Propbd= 1.0"WC
DSP IntTime= 40 sec
Bldg Static P Setup
[8=1or2 & 10=2]
DF CapCtrl= DuctPres
[8=1 or 2]
Remote DF Cap= 25%
[8=1 or 2]
Flush Econo= No
[4=1]
Eng Units= English
DSP Propbd= 6.0"WC
Duct Static P Setup
[8=1 or 2]
RAT Sensor= No
2nd P Sensor= None
[8=1 or 2]
Space Sensor= No
Htg Zero OAT= 0°F
Hol 13=mmmdd-mmmdd
AHU ID= _____
CCB1 ID= _____
[2=1]
CCB2 ID= _____
[2=1, & 3=7]
EHB1 ID= _____
[6=3]
Calibrate Mode= No
Sun= 00:00 - 00:00
Htg OAT= 35°F
Setup/Service
Unit Configuration
6
Sat= 00:00 - 00:00
Htg Rate= 0.4°F/min
Auto Update= Yes
Optimal Start= No
Space Temp= xxx.x°F
Optimal Start
Fri= 00:00 - 00:00
Hol 3=mmmdd-mmmdd
Hol 2=mmmdd-mmmdd
Hol 1=mmmdd-mmmdd
Holiday Schedule
Thu= 00:00 - 00:00
Operating Hours
Beg= mmm dd@hh:mm
Mon= 00:00 - 00:00
Wed= 00:00 - 00:00
One Event Schedule
Daily Schedule
5 Schedules
Configuration Code
DewPnt Db= 2°F
RH Db= 2%
DewPoint Spt= 50.0°F
RH Setpoint= 50%
Dehum Method=None
Dew Point= xx.x°F
Rel Humidity= xxx%
Dehum Status= _____
Dehumidification
[1=0 or 2]
B
Figure 2: Keypad accessible menu structure (continued)
McQuay OM-711-1
B
McQuay OM-711-1
OAT Sensor= Slow
Space Sensor= Slow
[1=0,1 or 3]
Return Sensor= Slow
[1=0 or 1]
Lo Airflow= Slow
[6=1 or 2]
Heat Fail= Slow
[6=1 or 2]
Fan Retry= Slow
[8=2]
Hi Pres Ckt1= Slow
[2=1]
Hi Pres Ckt2= Slow
[2=1]
Hi Pres Ckt3= Slow
[3=1,2,3,4,5 or 7]
Hi Pres Ckt4= Slow
[3=2,3,4 or 5]
Hi Pres Ckt5= Slow
[3=3]
Hi Pres Ckt6= Slow
[3=3]
Lo Pres Ckt1= Slow
[3=7]
Lo Pres Ckt2= Slow
[3=7]
OAT Sensor= Fast
Space Sensor= Fast
[1=2 or 3]
Return Sensor= Fast
[1=0 or 1]
Disch Sensor= Fast
Duct Hi Limit= Fast
[8=1 or 2]
Hi Return Temp= Fast
[1=0 or 1]
Hi Disch Temp= Fast
Alarm Name
Alarm Type
dd-mmm-yy hh:mm:ss
Previous Alarm 5
Alarm Name
Alarm Type
dd-mmm-yy hh:mm:ss
Alarm Name
Alarm Type
dd-mmm-yy hh:mm:ss
Previous Alarm 4
Alarm Name
Alarm Type
dd-mmm-yy hh:mm:ss
Fan Fail= Fast
OA Dmpr Stuck= Fast
[1=2 or 3]
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Previous Alarm 6
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Active Alarm 3
EWT Sensor= Slow
MAT Sensor= Fast
Active Alarm 2
Active Alarms
Freeze= Slow
[2=2 or 6=4]
MAT Sensor= Slow
Freeze= Fast
[2=2, 4=1 or 6=4]
Smoke= Fast
Lo Disch Temp= Fast
Alarm Out Problems
Alarm Out Faults
Active Alarm 1
7
OA Damper= Auto
Mod Cooling= Auto
[2=2]
Mod Heating= Auto
[6=4]
VAV Output= Heat
[8=1 or 2]
Disch Vanes= Auto
[8=1]
Disch VFD= Auto
[8=2]
Wtr Reg Vlv= Auto
Alarm= Normal
Economizer= Auto
[4=0or1]
Bypass Valve= Auto
Fan Operation= Off
Discharge Fan= Off
Manual Control= No
Manual Control
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Previous Alarm 7
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Active Alarm 4
Circ1 LP/Frst= Slow
[2=1]
Circ2 LP/Frst= Slow
[2=1]
Circ3 LP/Frst= Slow
[3=1,2,3,4,5 or 7]
Circ4 LP/Frst= Slow
[3=2,3,4 or 5]
Circ5 LP/Frst= Slow
[3=3]
Circ6 LP/Frst= Slow
[3=3]
Water Reg Vlv= Slow
[5=1]
No Water Flow= Slow
[5=0]
Frost-Ckt1= Slow
[3=7]
Frost-Ckt2= Slow
[3=7]
Comp #1 MP Alm= Slow
[2=1]
Comp #2 MP Alm= Slow
[2=1]
Comp #3 MP Alm= Slow
[3=1,2,3,4,5 or 7]
Comp #4 MP Alm= Slow
[3=2,3,4 or 5]
Comp #5 MP Alm= Slow
[3=3]
Comp #6 MP Alm= Slow
[3=3]
Previous Alarms
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Previous Alarm 8
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Previous Alarm 1
8
Pumpdown-Ckt1= Slow
[3=7]
Pumpdown-Ckt2= Slow
[3=7]
CompB1 Clg Ena= Slow
[2=1]
CompB2 Clg Ena= Slow
[3=3]
CompB1 Comm= Slow
[2=1]
CompB2 Comm= Slow
[3=3]
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Previous Alarm 2
Dirty Filter= Off
CompB1 H/W= Off
[2=1]
CompB2 H/W= Off
[3=3]
Airflow Switch= Off
Alarm Out Warnings
dd-mmm-yy hh:mm:ss
Alarm Type
Alarm Name
Previous Alarm 3
Lo Disch Alm= 40°F
Hi Return Alm= 120°F
[1=1 or 3]
Hi Disch Alm= 170°F
Alarm Limits
Figure 2: Keypad accessible menu structure (continued)
5
Sub Menus (Continued)
Display Format
The information stored in the MicroTech II controller menu
structure can be viewed on the 4-line by 20-character LCD
display. The current menu displays on the top line; and up to
three menu items display on the next three lines (see
Figure 3). The item lines contain one or more data fields that
convey varying information. A blinking cursor indicates the
current item. There is a “navigation” indicator on the right
side of the top line while in navigation mode. A symbol
indicates there are more items in the menu above the current
display window. A symbol indicates there are more items
in the menu below” the current display window. A
symbol indicates there are more items in the menu above and
below the current display window.
Figure 3: LCD display format
Navigation Indicator
Menu Line
Item Line
Item Line
Item Line
Temperatures
Disch Air=55.0°F
Return Air=73.5°F
Space Temp=74.5F
Blinking Cusor
1. Pressing the Down Arrow (-) key one time
changes the first field (blinking) to a value of 4.
2. Pressing the Right Arrow key one time moves
the blinking cursor to the second field.
3. Again pressing the Right Arrow key one time
(the second field will not be changed in this
example) moves the blinking cursor to the third
field.
4. Pressing the Down Arrow (-) key one time
changes the third field (now blinking) to a value
of 4.
5. Now the four fields should be 4545, the desired
password. Pressing the Enter/Save key enters the
password.
Data Field
Password Protection
The MicroTech II controller includes password protection to
guard against inadvertent control parameter changes. When
an attempt is made to change the value of an adjustable
parameter with the keypad, the controller prompts the user to
enter either the level 2 (L-2) or level 1 (L-1) password
depending on the level required for that particular parameter.
The L-2 password is 4545. The L-1 password is 6555.
Note: L-2 has a higher level of authority than L-1. The
controller prompts for the password by displaying the
following:
Figure 4: Password protection
**Enter L-2 Password
Password=5555
Blinking Data Field
6
The password fields initially have values off 5555 in them.
The first field is blinking. For example, to change the
password to 4545 and enter the new value, use the following
procedure:
If the correct password is entered, the display returns to the
item to change and the changeable item field blinks, waiting
to be modified.
Password Timeout
Once the password is entered, the controller allows further
changes without prompting the user to enter a password until
either the password timer expires or a different password
level is required for the particular parameter to be changed.
The password timer is adjustable from 2-60 minutes using
the Timeout= parameter in the Passwords menu.
Clear Alarm Password
Normally clearing an active alarm does not require a
password entry. This is true if the Clear Alarm= item in the
Passwords menu is set to “None.” However, if this parameter
is set to “L-1” the controller prompts the user to enter the
level 1 password before an alarm can be cleared. If this
parameter is set to “L-2” the controller prompts the user to
enter the level 2 password before an alarm can be cleared.
For details regarding alarm clearing, see “Keypad/Display
Exercises” on page 7.
McQuay OM-711-1
Keypad Functions
Enter/Save Key:
The MicroTech II controller keypad consists of 8 pressure
sensitive membrane switches. Refer to Figure 1 on page 2.
The following are descriptions of these keys and their
functions.
Pressing this key while viewing a menu on the
main menu changes the displayed menu to the
first menu of the menu group or category
associated with that menu. Pressing this key
while viewing a changeable menu item places
the keypad into “edit” mode. The first
changeable field for that parameter begins
blinking and the top line of the display is
replaced with **Edit Mode, indicating the
“edit” mode is activated. Once a parameter is
changed in “edit” mode, pressing this key
“saves” the new parameter value into memory.
When the new parameter value is saved, the
changeable field or field stops blinking and the
**Edit Mode message disappears from the top
line of the display, indicating the keypad is no
longer in “edit” mode.
Left Arrow Key:
Pressing this key changes the displayed menu
one menu to the left while navigating within the
menu structure. It also changes the field to be
edited one field to the left while editing a
parameter value.
Right Arrow Key:
Pressing this key changes the displayed menu
one menu to the right while navigating within
the menu structure. It also changes the field to
be edited one field to the right while editing a
parameter value.
Up Arrow (+) Key:
Pressing this key changes the displayed menu or
menu item up one menu or menu item while
navigating within the menu structure. It also
increments a changeable parameter one value
while editing.
Down Arrow (-) Key:
Pressing this key changes the displayed menu or
menu item down one menu or menu item while
navigating within the menu structure. It also
decrements a changeable parameter one value
while editing.
Alarm Key:
Pressing this key while the red LED above it on
the keypad is “on,” changes the displayed menu
to the Active Alarm 1 menu.
Clear Alarm Key:
Pressing this key while any of the active alarm
menus are being displayed sends a clear
command to clear the alarm.
Keypad/Display Exercises
The following are three exercises that serve as a guide
through some typical keypad operations. Note that often
there is more than one way to perform an operation.
Back/Cancel Key:
Changing Setpoints
Pressing this key while navigating within the
menu structure changes the displayed menu
back to the main menu. While editing a
changeable parameter, pressing this key causes
the edit session to be terminated and the
parameter value reverts to the value it had
before beginning the editing session. Pressing
this key after having pressed the Alarm key to
view an active alarm causes the display to revert
to the menu that was in the display prior to
pressing the Alarm key. Pressing this key while
at the main menu causes a manual password log
off and resets the password timer.
In this exercise, assume that the current cooling discharge air
setpoint is 55°F and is not quite meeting the system cooling
requirements. Using the following procedure, the cooling
discharge air setpoint is changed to 53°F.
1. Pressing the Back/Cancel key changes the
display back to the main menu if not
already there.
2. Assuming the blinking cursor is positioned
on the System Summary menu, pressing
the Down Arrow (-) key twice changes the
cursor position to the Temperature menu.
3. Pressing the Enter/Save key changes the
display to the Zone Cooling menu, the first
menu in the Temperatures group of menus.
McQuay OM-711-1
7
4. Pressing the Right Arrow key twice
changes the display to the Discharge
Cooling menu. The cursor is positioned on
the first item within this menu, which is
the Disch Air= item.
5. Pressing the Down Arrow (-) key three
times moves the display down three items
in the menu and positions the cursor on the
DAT Clg Spt= item.
When the Enter/Save key is pressed and if the
password timer has expired since the last time
the password was entered, the controller
prompts the user to enter a password at this
point. The procedure outlined in “Password
Protection” on page 6 must be followed to enter
the password. Once the password has been
successfully entered, the display enters the
“edit” mode as show below. When the
Enter/Save key is pressed and if a password
entry is not required, the display simply enters
the “edit” mode as shown below.
Menu Line
Item Line Being Edited
**Edit Mode
Cooling Capacity=25%
Eff Clg Spt=55.0°F
DAT Clg Spt=55.0F
Blinking Data Field
Note: The Menu Line has been replaced by
the “**Edit Mode” indication message,
the cursor has disappeared and the date
field to be edited is blinking.
6. Pressing the Down Arrow (-) key once
decrements the current DAT Clg Spt=
value by a tenth of a degree. Pressing and
holding the Down Arrow (-) causes the
value to decrement rapidly.
7. When the DAT Clg Spt= parameter is at
the desired value (53.0°F in this example),
pressing the Enter/Save key stores the new
setting and terminates the edit session.
Note: The data field stops blinking when the
new value is recorded and the display
leaves the “edit” mode.
8
Clearing Alarms
In this exercise, assume that a “fault” alarm exists. This type
of alarm shuts down the unit and keeps it off until the alarm
is manually cleared. If the conditions that caused the alarm
have been corrected, the following procedure is used to clear
a fault..
1. Pressing the Alarm key while the red LED
on the keypad is “on” (indicating an active
alarm condition), changes the display to the
Active Alarm 1 menu, which displays the
current highest priority alarm.
2. Pressing the Clear Alarm key send a clear
command to the controller. This clears the
alarm and returns the unit to normal
operation.
Modifying Schedules
In this exercise, assume that a change in building occupancy
requires the self-contained unit to run from 8:30 a.m. to 5:30
p.m. on Sunday. The current schedule has the unit shut down
on Sunday. Using the following procedure, this schedule
changes accordingly. This procedure assumes that the
password has been entered and the password timer has not
expired.
Note: The time schedule and time clock in the MicroTech II
controller uses “military” time. In this case 5:30 p.m.
is equivalent to 17:30 in “military” time.
1. Pressing the Back/Cancel key changes the
display to back to the main menu if not
already there.
2. Assuming the blinking cursor is positioned
on the System Summary menu, pressing
the Down Arrow (-) key three times
changes the cursor position to the
Schedules menu.
3. Pressing the Enter/Save key changes the
display to the Daily Schedule menu, the
first menu in the Schedules group of
menus.
4. Pressing the Down Arrow (-) key six times
moves the display down six items in the
menu and positions the cursor on the Sun=
item.
McQuay OM-711-1
5. When the Enter/Save key is pressed (and if
a password entry is not required) the
display enters the edit mode with the “start
hour” data field blinking.
6. Pressing the Up Arrow (+) key once
increments the current “start hour” value
by one hour. Pressing and holding the Up
Arrow (+) causes the value to increment
rapidly.
7. When the “start hour” is at the desired
value (08 in this example), pressing the
Right Arrow key moves the blinking
cursor to the “start minute” field.
8. Pressing the Up Arrow (+) key once
increments the current “start minute” value
by one minute. Pressing and holding the
Up Arrow (+) causes the value to
increment rapidly.
9. When the “start minute” is at the desired
value (30 in this example), pressing the
Right Arrow key moves the blinking
cursor to the “stop hour” field.
10. Pressing the Up Arrow (+) key once
increments the current “stop hour” value
by one hour. Pressing and holding the Up
Arrow (+) causes the value to increment
rapidly.
Keypad/Display Menu Reference
The following is a brief description of each menu and menu
item within the Vertical Self-Contained MicroTech II menu
structure. Tables are included that show every menu, item,
and field in the menu structure of the program. These menus
and items can all be displayed with the keypad/display.
Note: There are a number of instances where the same
menu item appears under more than one menu.
System Summary
Menus in the System Summary category contain basic unit
operating status and control setpoint parameters. Table 2 on
page 11 lists all menus and items in the System Summary
group or category. The “Range” column in the table lists all
possible values for each item. The factory settings for the
adjustable parameters are shown in the “Factory Default
Value” column. The following are brief descriptions of the
System Summary category menus and items.
System
The System menu provides a summary of basic unit status
and control items.
UnitStatus. UnitStatus= is a status only item that indicates
the state in which the unit is currently operating. For detailed
information regarding this parameter, refer to “Determining
Unit Status” on page 38.
Clg Capacity. Clg Capacity= is a status only item that
indicates the percentage of the unit maximum cooling
capacity currently operating.
Htg Capacity. Htg Capacity= is a status only item that
indicates the percentage of the unit maximum heating
capacity currently operating.
11. When the “stop hour” is at the desired
value (17 in this example), pressing the
Right Arrow key moves the blinking
cursor to the “stop minute” field.
Clg Status. Clg Status= is a status only item that indicates
whether or not cooling (economizer and/or mechanical) is
currently allowed. If cooling is disabled, the reason is
indicated. For detailed information regarding this parameter,
refer to “Determining Unit Status” on page 38.
12. Pressing the Up Arrow (+) key once
increments the current “stop minute” value
by one minute. Pressing and holding the
Up Arrow (+) causes the value to
increment rapidly.
Htg Status. Htg Status= is a status only item that indicates
13. When the “stop minute” is at the desired
value (30 in this example), pressing the
Enter/Save key stores the new Sun=
start/stop setting and terminates the edit
session.
14. The data field stops blinking when the new
value is recorded and the display leaves the
edit mode.
McQuay OM-711-1
whether or not heating is currently allowed. If heating is
disabled, the reason is indicated. For detailed information
regarding this parameter, refer to “Determining Unit Status”
on page 38.
Ctrl Mode. Ctrl Mode= is an adjustable item that allows the
unit to be set for manual off, cooling only, heating only, fan
only or auto heating/cooling operation. For detailed
information regarding this parameter, refer to “Auto/Manual
Operation” on page 40.
Note: If this item is set to “Auto,” then cooling only,
heating only, fan only or auto heating/cooling
operation is determined by a network signal as
indicated by the Appl Mode= item.
Appl Mode. Appl Mode= is a network adjustable item that
indicates that the unit is set for network off, cooling only,
9
heating only, fan only or auto heating/cooling operation via a
network signal. For detailed information regarding this
parameter, refer to “Auto/Manual Operation” on page 40.
Note: This item has no affect on the unit operation unless
the Ctrl Mode= item is set to “Auto.”
VAV Output. VAV Output= is a status only item that
indicates the status of the VAV Box Output (MCB-BO12).
This output is provided for field use for interlocking field
VAV box operation with the unit heating or cooling
operation. This output is OFF (Heat) when the unit is in any
heating operating state (including Recirc) and ON (Cool) in
any other operating state. For detailed information regarding
this output, refer to “Operating States and Sequences” on
page 57 and the “Field Wiring” section of IM710, MicroTech
II Vertical Self-Contained Unit Controller
Outside Damper Output. Outdr Damper = is a status only
item that indicates the status of the Outside Damper Output
(MCB-BO2). For detailed information regarding this output,
refer to “Operating States and Sequences” on page 57 and
the “Field Wiring” section of IM710, MicroTech II Vertical
Self-Contained Unit Controller.
Occupancy
Menus in the Occupancy menu contain status and control
items that relate to unit occupied/unoccupied operation.
Occupancy. Occupancy= is a status only item that indicates
whether the unit is currently in an occupied, unoccupied, or
tenant override mode of operation. For detailed information
regarding this parameter, refer to “Determining Unit Status”
on page 38.
Occ Mode. Occ Mode= is an adjustable item that allows the
unit to be set for manual occupied or unoccupied operation,
automatic operation based on a time schedule input or
manual tenant override operation. For detailed information
regarding this parameter, refer to “Auto/Manual Operation”
on page 40.
Occ Src. Occ Src= is status only item that indicates the
input source or function that is responsible for setting the
Occupancy= parameter to “Occ.” For detailed information
regarding this parameter, refer to “Auto/Manual Operation”
on page 40.
Tenant Override. Tnt Ovrd= is an adjustable item that
indicates the tenant override time remaining when the unit is
operating due to tenant override operation. For detailed
information regarding this parameter, refer to “Auto/Manual
Operation” on page 40.
Emerg Override . Emerg Override= is an adjustable item
that provides a means of completely shutting off a unit via a
network signal. If this parameter is set to “Off” the unit can
not start based on a time clock or any other means. The only
way the unit can be started is to change this parameter to
“Norm.” For detailed information regarding this parameter,
refer to “Auto/Manual Operation” on page 40.
10
Temperatures
Menus in the Temperatures menu contain unit temperature
status information.
Control Temp. Control Temp= is a status only item that
displays the current value of the “Control Temperature.” The
“Control Temperature” is defined as the temperature input
selected by the CtrlTemp Src= parameter in the Zone Cooling
or Zone Heating menu. For example, if the CtrlTemp Src=
parameter is set to “Return,” then the Control Temp=
parameter reads the same value as the Return Air= parameter.
For detailed information regarding this parameter, refer to
“Heat/Cool Changeover” on page 62.
Disch Air. Disch Air = is a status only item that displays the
current temperature reading from the unit discharge air
temperature sensor. This sensor is standard on all units.
Return Air. Return Air= is a status only item that displays
the current temperature reading from the unit return air
temperature sensor. This sensor is standard on all units with
return air.
Space Temp. Space Temp= is a status only item that
displays the current space (or zone) temperature reading
from the optional unit space air temperature sensor input.
Refer to “Zone (Space) Temperature Sensor” on page 52.
Note: If an optional space temperature sensor is not
installed, the Space Sensor= item in the Unit
Configuration menu should be set to “No” to disable
the alarm function associated with an open circuit at
the space temperature sensor input.
OA Temp. OA Temp= is a status only item that displays the
current temperature reading from the optional field mounted
outdoor air temperature sensor. If an optional OA
Temperature Sensor is not installed, the OA Temp=Item in
the unit configuration menu should be set to “No” to disable
the alarm function associated with an open circuit at the OA
Temperature Sensor input.
Mixed Air Temperature. MAT = is a status only item that
displays the current temperature reading from the unit
mounted mixed air temperature sensor. The sensor is
standard on all units.
Entering Water Temperature. EWT = is a status only item
that displays the current temperature reading from the unit
mounted entering water temperature sensor. The sensor is
standard on all water-cooled units.
Leaving Water Temperature. LWT = is a status only item
that displays the current temperature reading from the unit
mounted leaving water temperature sensor. The sensor is
standard on all water-cooled units.
McQuay OM-711-1
Table 2: System summary menus
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
Off Unoc
Off Man
Off Net
Off Sw
Off Alm
Calib
Startup
Recirc
Fan Only
UnitStatus
-
-
Econo
Cooling
MWU
Heating
Min DAT
UnocEcon
UnocFanO
UnocDAT
UnocClg
UnocHtg
Man Ctrl
Clg Capacity
-
-
Htg Capacity
-
-
0-100%
0-100%
All Clg Ena
Econo
Mech Clg
Off Amb
System
Clg Status
-
-
Off Alm
Off No Flo
Off None
Off Sw
Off Net
Off Man
Htg Ena
Off Amb
Off Alm
Htg Status
-
-
Off None
Off Sw
Off Net
Off Man
Off
Auto
Ctrl Mode
Auto
1
Heat/Cool
Heat Only
Cool Only
Fan Only
Off
Heat/Cool
Appl Mode
Heat/Cool
1
Heat Only
Cool Only
Fan Only
Outdr Damper
McQuay OM-711-1
-
-
Open
Close
11
Table 2: System summary menus (continued)
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
Occupancy
-
-
UnocClg
Occ
Tnt Ovrd
Occ
Occ Mode
Auto
1
UnocClg
Tnt Ovrd
Auto
Occupancy
None
Int Sched
Occ Src
-
-
Net Sched
Occ Mode
Remote Sw
Temperatures
Tnt Ovrd
0 min
1
0 -300 min
Emerg Override
Norm
1
Control Temp
-
-
-50 - 250.0 °F
Norm
Off
Disch Air
-
-
-50 - 250.0 °F
Return Air
-
-
-50 - 250.0 °F
Space Temp
-
-
-50 - 250.0 °F
OA Temp
-
-
-50 - 250.0 °F
MAT
-
-
-50 - 250.0 °F
EWT
-
-
-50 - 250.0 °F
LWT
-
-
-50 - 250.0 °F
Menu Item Name
Factory Default Value
Field Number
Range
Flow Status
-
-
Disch Fan
-
-
Fan Operation
-
-
Head Pressure Comp1
-
-
0 - 450 psi
Head Pressure Comp2
-
-
0 - 450 psi
Setpoint
160 psi
1
140 - 210 psi
Water Flow
-
-
Table 3: Air/water flow
Menu Name
Air Flow Summary
Head Pressure
Water Flow Summary
Air/Water Flow
Menus in the Air/Water Flow category contain status and
control setpoint parameters that define the airflow control
setup of the unit. Table 4 on page 14 lists all menus and items
in the Air/Water Flow group or category. The “Range”
column in the table lists all possible values for each item. The
factory settings for the adjustable parameters are shown in the
“Factory Default Value” column. Below are brief descriptions
of the Air/Water Flow category menus and items.
Water flow Summary
The Water flow Summary menu contains status information
related to unit water flow.
Water Flow. Water Flow = is a status only item that
indicates whether or not water flow is detected. Water flow
12
Flow
NoFlow
On
Off
On
Off
Yes
No
status is sensed by a binary input delivered to the controller
by a waterflow sensor (WF1).
Head Pressure
The Head Pressure menu contains parameters that are used
to maintain head pressure control. For detailed information
regarding Head Pressure control, refer to “Water Regulating
Valve Control” on page 65.
Head Pressure Comp1. HdPres Cmp1= is a status only
item that indicates the current refrigerant pressure for circuit
#1.
Head Pressure Comp2. HdPres Cmp2= is a status only
item that indicates the current refrigerant pressure for circuit
#2.
McQuay OM-711-1
Head Pressure Setpoint. Setpoint= is an adjustable item
Bldg Press. Bldg Press= is a status only item that indicates
that sets the refrigerant setpoint used for controlling the
water regulating valve. The water-regulating valve is
modulated to maintain the refrigerant pressure.
the current pressure at the building static pressure sensor
location.
Airflow Summary
The Airflow Summary menu contains status information
related to unit airflow, static pressure and fan operation.
Flow Status. Flow Status= is a status only item that
indicates whether or not discharge airflow is detected.
Airflow status is sensed by a binary input delivered to the
controller by a differential pressure switch (PC7).
Disch Fan. Disch Fan= is a status only item that indicates
whether or not the controller is commanding the unit
discharge fan on.
BldgSP Spt. BldgSP Spt= is an adjustable item that sets the
building static pressure setpoint used for controlling the fan
inlet vanes or AFD. The inlet vanes or AFD is modulated to
maintain the building static pressure sensor input at this
setpoint.
BSP Db. BSP Db= is an adjustable item that sets a deadband
around the BldgSP Spt= parameter in the Bldg Static
Pressure menu. No building static pressure control action is
taken when the current building static pressure input is
within this deadband.
Fan Operation. Fan Operation= is a status only item that
indicates the on/off status of the Fan Operation Output
(MCB-BO3). For details regarding the Fan Operation
Output, refer to the “Field Output Signals” section of IM710,
MicroTech II Vertical Self-Contained Unit Controller
Duct Pressure
The Duct Pressure menu contains parameters that are used to
maintain duct static pressure control. For detailed
information regarding discharge fan capacity control, refer to
“Discharge Fan Capacity Control” on page 81.
Duct Press. Duct Press= is a status only item that indicates
the current pressure at the duct static pressure sensor
location. When a unit is equipped with two duct static
pressure sensors, this item displays the lower of the two
sensor readings. Static pressure control is then based on the
lower of the two readings.
DuctSP Spt. DuctSP Spt= is an adjustable item that sets the
duct static pressure setpoint used for controlling the
discharge air fan inlet vanes or AFD. The inlet vanes or AFD
is modulated to maintain the duct static pressure sensor input
at this setpoint.
DSP Db. DSP Db= is an adjustable item that sets a deadband
around the DuctSP Spt= parameter in the Duct Static
Pressure menu. No duct static pressure control action is
taken when the current duct static pressure input is within
this deadband.
Disch Fan Cap. Disch Fan Cap= is a status only item that
indicates the current discharge fan capacity. 0-100% inlet
vane position is indicated if the unit is equipped with
discharge air fan variable inlet vanes. 0-100% of AFD
maximum speed is indicated if the unit is equipped with a
discharge air fan AFD.
Bldg Pressure
The Bldg Pressure menu contains parameters that are used to
maintain building static pressure control. For detailed
information regarding building static pressure control, refer
to “Direct Building Static Pressure Control” on page 82.
McQuay OM-711-1
13
Table 4: Airflow/waterflow menus
Menu Name
Menu Item Name
Factory Default Value
Field Number
Water Flow Summary
Water Flow
-
-
HdPress Comp1
-
-
0 - 450 psi
HdPress Comp2
-
-
0 - 450 psi
Setpoint
160 psi
1
140-210 psi
Flow Status
-
-
Disch Fan
-
-
Head Pressure
Air Flow Summary
Fan Operation
-
-
Duct Press
Duct Static Pressure
Bldg Static Pressure
Yes
No
Flow
No Flow
On
Off
On
Off
-
0.00 - 4.00 “WC
DuctSP Spt
1.00 “WC
1
0.20 - 4.00 “WC
DSP Db
0.08 “WC
1
0.01 - 0.50 “WC
Disch Fan Cap
-
-
0 - 100%
Bldg Press
-
-
-0.250 - +0.250 “WC
BldgSP Spt
0.050 “WC
1
-0.250 - +0.250 “WC
BSP Db
0.010 “WC
1
0.001 - 0.100 “WC
Temperature
Menus in the Temperature category contain status and
control setpoint parameters that define the temperature
control setup of the unit. Table 5 on page 19 lists all menus
and items in the Temperature group or category. The
“Range” column in the table lists all possible values for each
item. The factory settings for the adjustable parameters are
shown in the “Factory Default Value” column. The
following are brief descriptions of the Temperature category
menus and items.
Zone Cooling
The Zone Cooling menu primarily contains basic status and
control parameters that relate to or affect the unit changeover
into cooling operation. For detailed information regarding
unit heating/cooling changeover, refer to “Heat/Cool
Changeover” on page 62.
Control Temp. Control Temp= is a status only item that
displays the current value of the “Control Temperature.” The
“Control Temperature” is defined as the temperature input
selected by the CtrlTemp Src= parameter in the Zone Cooling
or Zone Heating menu. For example, if the CtrlTemp Src=
parameter is set to “Return,” then the Control Temp= parameter
reads the same value as the Return Air= parameter. For more
information regarding this parameter, refer to “Heat/Cool
Changeover” on page 62.
Clg Capacity. Clg Capacity= is a status only item that
indicates the percentage of the unit maximum cooling
capacity currently operating.
Eff Clg Spt. Eff Clg Spt= is a status only item that indicates
the cooling changeover setpoint currently in effect. When the
current value of the Control Temp= parameter rises above
14
Range
this parameter by more than half the Clg Deadband=
parameter, cooling operation is enabled. When the current
value of the Control Temp= parameter drops below this
parameter by more than half the Clg Deadband= parameter
cooling operation is disabled. This parameter is set by the
controller to same value as the Occ Clg Spt= parameter.
Occ Clg Spt. Occ Clg Spt= is an adjustable item used by the
controller to set the Eff Clg Spt= parameter. The Eff Clg
Spt= is set to this value.
Clg Deadband. Clg Deadband= is an adjustable item that
sets a deadband around the Eff Clg Spt= parameter. For
example, if the Eff Clg Spt= parameter is set to 75ºF and the
Clg Deadband= parameter is set to 2ºF the deadband around
the setpoint would be from 76.0ºF to 74.0ºF.
CtrlTemp Src. CtrlTemp Src= is an adjustable item that
selects the temperature sensor input to be used for the unit
heating/cooling changeover decision. For example, if the
CtrlTemp Src= parameter is set to “Return,” then the Control
Temp= parameter reads the same value as the Return Air=
parameter. For detailed information regarding this parameter,
refer to “Heat/Cool Changeover” on page 62.
Space Temp. Space Temp= is a status only item that
displays the current space (or zone) temperature reading
from the optional unit space air temperature sensor input.
Refer to “Zone (Space) Temperature Sensor” on page 52.
Note: If an optional space temperature sensor is not
installed, the Space Sensor= item in the Unit
Configuration menu should be set to “No” to disable
the alarm function associated with an open circuit at
the space temperature sensor input.
McQuay OM-711-1
UnoccClg Spt. UnoccClg Spt= is an adjustable item that
Htg Capacity. Htg Capacity= is a status only item that
sets the point at which the unit starts up and provides
unoccupied cooling (night setup) during unoccupied periods.
For detailed information regarding unoccupied cooling
operation, refer to “Unoccupied Cooling (Night Setup)” on
page 83.
indicates the percentage of the unit maximum heating
capacity currently operating.
Note: An optional space temperature sensor is required for
unoccupied cooling operation.
UnoccClgDiff. UnoccClgDiff= is an adjustable item that sets
a differential above the UnoccClg Spt= parameter. Once
activated, unoccupied cooling operation is terminated when
the Space Temp= value falls below the UnoccClg Spt=
setting by more than this differential.
Clg Status. Clg Status= is a status only item that indicates
whether or not cooling (economizer and/or mechanical) is
currently allowed. If cooling is disabled, the reason is
indicated. For detailed information regarding this parameter,
refer to “Determining Unit Status” on page 38.
Min EWT. Min EWT= is an adjustable item that sets the
minimum allowable entering water temperature. Mechanical
Cooling is disabled when the entering water temperature
sensor input falls below this setpoint.
Min EWT Diff. Min EWT Diff= is an adjustable item that
sets a differential above the Min EWT= parameter.
Compressor operation is re-enabled when the entering water
temperature sensor input rises above the Min EWT= value by
more than this differential.
OAT Comp Lock. OAT Comp Lock= is an adjustable item
that sets the low outdoor air temperature mechanical cooling
lockout point. Mechanical cooling operation is disabled
when the outdoor air temperature sensor input falls below
this setpoint.
OAT Lock Diff. OAT Lock Diff= is an adjustable item that
sets a differential above the OAT Comp Lock= parameter.
Mechanical cooling operation is enabled when the outdoor
air temperature sensor input rises above the OAT Comp
Lock= valve by more than this differential.
Zone Heating
The Zone Heating menu primarily contains basic status and
control parameters that relate to or affect the unit changeover
into heating operation. For detailed information regarding
unit heating/cooling changeover, refer to “Heat/Cool
Changeover” on page 62.
Control Temp. Control Temp= is a status only item that
displays the current value of the “Control Temperature.” The
“Control Temperature” is defined as the temperature input
selected by the CtrlTemp Src= parameter in the Zone
Cooling or Zone Heating menu. For example, if the
CtrlTemp Src= parameter is set to “Return,” then the Control
Temp= parameter reads the same value as the Return Air=
parameter. For detailed information regarding this parameter,
refer to “Heat/Cool Changeover” on page 62.
McQuay OM-711-1
Eff Htg Spt. Eff Htg Spt= is a status only item that indicates
the heating changeover setpoint currently in effect. When the
current value of the Control Temp= parameter, falls below
this parameter by more than half the Htg Deadband=
parameter, heating operation is enabled. When the current
value of the Control Temp= parameter rises above this
parameter by more than half the Htg Deadband= parameter
heating operation is disabled. This parameter is set by the
controller to same value as the Occ Htg Spt= parameter.
Occ HtgSpt. Occ Htg Spt= is an adjustable item used by the
controller to set the Eff Htg Spt= parameter. The Eff Htg
Spt= is set to this value.
Htg Deadband. Htg Deadband= is an adjustable item that
sets a deadband around the Eff Htg Spt= parameter. For
example, if the Eff Htg Spt= parameter is set to 70ºF and the
Htg Deadband= parameter is set to 2ºF the deadband around
the setpoint would be from 68.0ºF to 72.0ºF.
CtrlTemp Src. CtrlTemp Src= is an adjustable item that
selects the temperature sensor input to be used for the unit
heating/cooling changeover decision. For example, if the
CtrlTemp Src= parameter is set to “Return,” then the Control
Temp= parameter reads the same value as the Return Air=
parameter. For detailed information regarding this parameter,
refer to “Heat/Cool Changeover” on page 64.
Space Temp. Space Temp= is a status only item that
displays the current space (or zone) temperature reading
from the optional unit space air temperature sensor input.
Refer to “Zone (Space) Temperature Sensor” on page 52.
Note: If an optional space temperature sensor is not
installed, the Space Sensor= item in the Unit
Configuration menu should be set to “No” to disable
the alarm function associated with an open circuit at
the space temperature sensor input.
UnoccHtg Spt. UnoccHtg Spt= is an adjustable item that
sets the point at which the unit starts up and provides
unoccupied heating (night setback) during unoccupied
periods. For detailed information regarding unoccupied
heating operation, refer to “Unoccupied Heating (Night
Setback)” on page 88.
Note: An optional space temperature sensor is required for
unoccupied heating operation.
UnoccHtgDiff. UnoccHtgDiff= is an adjustable item that
sets a differential above the UnoccHtg Spt= parameter. Once
activated, unoccupied heating operation is terminated when
the Space Temp= value rises above the UnoccHtg Spt=
setting by more than this differential.
Htg Status. Htg Status= is a status only item that indicates
whether or not heating is currently allowed. If heating is
disabled, the reason is indicated.
15
OATHtg Lock. OATHtg Lock= is an adjustable item that sets
the high outdoor air temperature heating lockout point.
Heating operation is disabled when the outdoor air
temperature sensor input rises above this setpoint.
For detailed information on discharge air temperature
setpoint reset, refer to “Cooling Discharge Setpoint Reset”
on page 76.
a differential below the OATHtg Lock= parameter. Heating
operation is re-enabled when the outdoor air temperature
sensor input below the OATHtg Lock= value by more than
this differential.
Clg Reset. Clg Reset= is an adjustable item that is use to
activate a cooling discharge air temperature reset schedule
and to select the input to be used as a basis for the reset. For
detailed information on discharge air temperature setpoint
reset, refer to “Cooling Discharge Setpoint Reset” on page
76.
Discharge Cooling
Min Clg Spt@. Min Clg Spt@= is an adjustable item that
OATLock Diff. OATLock Diff= is an adjustable item that sets
The Discharge Cooling menu contains parameters that relate
to or are used to maintain the discharge temperature when
the unit is changed over into cooling operation. For detailed
information regarding cooling operation, refer to “Heat/Cool
Changeover” on page 62, “Economizer” on page 64,
“Cooling: Multistage” on page 67, and “Cooling:
Modulating” on page 72, as applicable.
Disch Air. Disch Air = is a status only item that displays the
current temperature reading from the unit discharge air
temperature sensor. This sensor is standard on all units.
Clg Capacity. Clg Capacity= is a status only item that
indicates the percentage of the unit maximum cooling
capacity currently operating.
Eff Clg Spt. Eff Clg Spt= is a status only item that indicates
the cooling discharge air temperature setpoint currently in
effect. When the unit is in a cooling operating state,
economizer dampers and/or mechanical cooling capacity are
controlled to maintain the unit discharge air temperature
input at this setpoint. The Eff Clg Spt= parameter is either set
by the controller to the DAT Clg Spt= value or is set to a
value based on the results of a discharge air temperature
reset schedule. For detailed information regarding discharge
air temperature setpoint reset, refer to“Cooling Discharge
Setpoint Reset” on page 79.
DAT Clg Spt. DAT Clg Spt= is an adjustable item used by
the controller to set the Eff Clg Spt= parameter. The Eff Clg
Spt= parameter is set to this value when it is not being set by
a reset schedule. For detailed information regarding
discharge air temperature setpoint reset, refer to “Cooling
Discharge Setpoint Reset” on page 76.
Clg Db. Clg Db= is an adjustable item that sets a deadband
around the Eff Clg Spt= parameter. For example, if the Eff
Clg Spt= parameter is set to 55ºF and the Clg Db= parameter
is set to 1ºF the deadband around the setpoint would be from
55.5ºF to 54.5ºF.
Min Clg Spt. Min Clg Spt= is an adjustable item that sets the
minimum cooling discharge setpoint for use with a cooling
discharge air temperature setpoint reset schedule. For
detailed information on discharge air temperature setpoint
reset, refer to “Cooling Discharge Setpoint Reset” on page
76.
Max Clg Spt. Max Clg Spt= is an adjustable item that sets
the maximum cooling discharge setpoint for use with a
cooling discharge air temperature setpoint reset schedule.
16
sets the value of the sensor input, selected with the Clg
Reset= parameter, at which the Eff Clg Spt= parameter is
reset to the Min Clg Spt= value. For detailed information
regarding discharge air temperature setpoint reset, refer to
“Cooling Discharge Setpoint Reset” on page 76.
Max Clg Spt@. Max Clg Spt@= is an adjustable item that
sets the value of the sensor input, selected with the Clg
Reset= parameter, at which the Eff Clg Spt= parameter is
reset to the Max Clg Spt= value. For detailed information
regarding discharge air temperature setpoint reset, refer to
“Cooling Discharge Setpoint Reset” on page 76.
Waterside Economizer
Waterside Economizer menu contains parameters that relate
to or are used to control the unit waterside economizer valve.
For detailed information regarding waterside economizer
valve control, refer to “Economizer” on page 64.
Discharge Air Temperature. Disch Air= is a status only
item that displays the current temperature reading from the
unit discharge air temperature sensor. This sensor is standard
on all units.
Economizer Position. Econo Pos= is a status only item
that indicates the current waterside economizer valve
position.
Entering. Water Temperature. EWT = is a status only item
that displays the current temperature reading from the unit
mounted entering water temperature sensor. The sensor is
standard on all water-cooled units.
EWT Diff. EWT Diff= is an adjustable item that sets a
differential below the MAT= parameter. Waterside
Economizer operation is enabled when the entering water
temperature sensor drops below the mixed air temperature
sensor by more than this differential.
Airside Economizer
The Airside Economizer menu contains parameters that
relate to or are used to control the Airside Economizer
Dampers. For detailed information regarding outdoor air
damper control, refer to “Economizer” on page 64.
OA Damper Pos. OA Damper Pos= is a status only item
that indicates the current outdoor air damper position.
Eff Min OA Pos. Eff Min OA Pos= is a status only item that
indicates the minimum outdoor air minimum position setpoint
currently in effect. Economizer dampers are controlled to
maintain this position whenever minimum ventilation is
McQuay OM-711-1
required. For detailed information regarding minimum
ventilation control, refer to “Minimum Ventilation Control
(Airside Economizer Only)” on page 66.
OA Ambient. OA Ambient= is a status only item that
indicates whether or not the outdoor air is suitable for free
cooling. If it is, “Low” is displayed. If not, “High” is
displayed. The free cooling decision can be based on either
an enthalpy switch input to the controller or on a dry bulb
OA temperature setpoint. This decision is made via the
EconChgovr= parameter. For detailed information regarding
economizer changeover operation refer to “Economizer
Changeover Method (Airside)” on page 65 and “Economizer
Changeover Method (Waterside)” on page 65.
MinOA Pos. MinOA Pos= is an adjustable item used by the
controller to set the Eff Min OA Pos= parameter. Eff Min OA
Pos= Min OA Pos if Eff Min OA Pos is not provided via a
network. For detailed information regarding minimum
ventilation control, refer to “Minimum Ventilation Control
(Airside Economizer Only)” on page 66.
EconChgovr. EconChgovr= is an adjustable item that
defines the method used to make the economizer changeover
decision. When EconChgovr= is set to “Enthalpy,” the
economizer changeover decision is based on the enthalpy
switch input to the controller. When the switch is closed, the
OA Ambient= item indicates “Low” and economizer
operation is enabled. When the switch is open, the OA
Ambient= item indicates “High” and economizer operation
is disabled. When EconChgover= is set to “Dry Bulb,” the
economizer changeover decision is based on the outdoor air
temperature compared to the EconChgovrT= item. When the
outdoor air temperature is below the EconChgovr T= value,
the OA Ambient= item indicates “Low” and economizer
operation is enabled. When the outdoor air temperature is
above the EconChgovr T= value, the OA Ambient= item
indicates “High” and economizer operation is disabled. For
detailed information regarding economizer changeover
operation refer to “Economizer Changeover Method
(Airside)” on page 65 and “Economizer Changeover Method
(Waterside)” on page 65.
EconChgovrT. EconChgovrT= is an adjustable item used to
make the economizer changeover decision when the
EconChgovr= parameter is set to “Dry Bulb.” It sets the
point below or above which the outdoor air temperature
enables or disables economizer operation. If the
EconChgovr= parameter is set to “Enthalpy,” this parameter
has no effect on the unit operation. For detailed information
regarding economizer changeover operation refer to
“Economizer Changeover Method (Airside)” on page 65 and
“Economizer Changeover Method (Waterside)” on page 65.
EconChgovrDiff. EconChgovrDiff= is an adjustable item
that sets a differential above the EconChgovrT= parameter.
When the EconChgovr= parameter is set to “Dry Bulb,”
economizer operation is disabled when the OA Temp=
parameter indicates a value above the EconChgovrT=
parameter by more than this differential. If the
McQuay OM-711-1
EconChgovr= parameter is set to “Enthalpy,” this parameter
has no effect on the unit operation. For detailed information
regarding economizer changeover operation refer to
“Economizer Changeover Method (Airside)” on page 65 and
“Economizer Changeover Method (Waterside)” on page 65.
Max Purge. Max Purge= is an adjustable item that sets the
maximum time prior to occupancy that the units purge
feature can be activated. This feature functions only when an
optional space (or zone) temperature sensor is installed and
when a unit internal time schedule is being used. For detailed
information regarding the purge feature, refer to “Purge” on
page 84.
OA Temp. OA Temp= displays the current temperature
reading from the unit mounted outdoor air temperature
sensor. This sensor is standard on all units.
Discharge Heating
The Discharge Heating menu contains parameters that relate
to or are used to maintain the discharge temperature when
the unit is changed over into heating operation. For detailed
information regarding heating operation, refer to “Heat/Cool
Changeover” on page 62, “Heating: Multistage” on page 73,
and “Heating: Modulating Temperature Control” on page 74,
as applicable.
Disch Air. Disch Air= is a status only item that displays the
current temperature reading from the unit discharge air
temperature sensor. This sensor is standard on all units.
Htg Capacity. Htg Capacity= is a status only item that
indicates the percentage of the unit maximum heating
capacity currently operating.
Eff Htg Spt. Eff Htg Spt= is a status only item that indicates
the heating discharge air temperature setpoint currently in
effect. When the unit is in a heating operating state, heating
capacity is controlled to maintain the unit discharge air
temperature input at this setpoint (except when unit is
equipped with single stage heat). The Eff Htg Spt=
parameter is either set by the controller to the DAT Htg Spt=
value or based on the results of a discharge air temperature
reset schedule. For detailed information regarding discharge
air temperature setpoint reset, refer to “Heating Discharge
Setpoint Reset” on page 79.
DAT Htg Spt. DAT Htg Spt= is an adjustable item used by
the controller to set the Eff Htg Spt= parameter. The Eff Htg
Spt= is set to this value when it is not being set by a reset
schedule. For detailed information regarding discharge air
temperature setpoint reset, refer to “Heating Discharge
Setpoint Reset” on page 79.
Htg Db. Htg Db= is an adjustable item that sets a deadband
around the Eff Htg Spt= parameter. For example, if the Eff
Htg Spt= parameter is set to 100ºF and the Htg Db=
parameter is set to 1ºF the deadband around the setpoint
would be from 100.5ºF to 99.5ºF.
Min DAT Ctrl. Min DAT Ctrl= is an adjustable item used to
activate or deactivate the low discharge temperature limit
function available on units equipped with modulating or
17
multistage heat. For detailed information regarding the low
discharge temperature limit function, refer to “Discharge Air
Low Limit Control” on page 74 (multistage heat) or
“Discharge Air Low Limit Control” on page 75 (modulating
heat) as applicable.
Min Htg Spt. Min Htg Spt= is an adjustable item that sets the
minimum heating discharge setpoint for use with a heating
discharge air temperature setpoint reset schedule. For
detailed information regarding discharge air temperature
setpoint reset, refer to “Heating Discharge Setpoint Reset”
on page 79.
Max Htg Spt. Max Htg Spt= is an adjustable item that sets
the maximum heating discharge setpoint for use with a
heating discharge air temperature setpoint reset schedule.
For detailed information regarding discharge air temperature
setpoint reset, refer to “Heating Discharge Setpoint Reset”
on page 79.
Htg Reset. Htg Reset= is an adjustable item that is used to
activate a heating discharge air temperature reset schedule
and to select the input to be used as a basis for the reset. For
detailed information regarding discharge air temperature
setpoint reset, refer to “Heating Discharge Setpoint Reset”
on page 79.
Min Htg Spt@. Min Htg Spt@= is an adjustable item that
sets the value of the sensor input, selected with the Htg
Reset= parameter, at which the Eff Htg Spt= parameter is
reset to the Min Htg Spt= value. For detailed information
regarding discharge air temperature setpoint reset, refer to
“Heating Discharge Setpoint Reset” on page 79.
Max Htg Spt@. Max Htg Spt@= is an adjustable item that
sets the value of the sensor input, selected with the Htg
Reset= parameter, at which the Eff Htg Spt= parameter is
reset to the Max Htg Spt= value. For detailed information
regarding discharge air temperature setpoint reset, refer to
“Heating Discharge Setpoint Reset” on page 79.
18
McQuay OM-711-1
Table 5: Schedules menu
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
Control Temp
-
-
-50.0 - 250°F
Clg Capacity
-
-
0-100%
Eff Clg Spt
-
-
0.0 - 99.0°F
Occ Clg Spt
75.0°F
1
0.0 - 99.0°F
Clg Deadband
1.0°F
1
1.0 - 9.9°F
Return
CtrlTemp Src
Return
1
Space
OAT
MAT
Space Temp
-
-
-50.0 - 250.0°F
UnoccClg Spt
85.0°F
1
55.0 - 99.0°F
UnocClgDiff
3.0°F
1
1.0 - 10.0°F
All Clg Ena
Zone Cooling
Econo
Mech Clg
Off Amb
Clg Status
-
-
Off Alarm
Off None
Off No Flo
Off Sw
Off Net
Off Man
Min EWT
55.0°F
1
20.0 - 100.0°F
Min EWT Diff
3.0°F
1
0.0 - 10.0°F
OAT Comp Lock
55.0°F
1
0.0 - 100.0°F
OAT Lock Diff
1.0°F
1
0.0 - 10.0°F
Control Temp
-
-
-50.0 - 250°F
Htg Capacity
-
-
0-100%
Eff Htg Spt
-
-
0.0 - 99.0°F
Occ Htg Spt
70.0°F
1
0.0 - 99.0°F
Htg Deadband
1.0°F
1
1.0 - 9.9°F
Return
Ctrl Temp Src
Return
1
Space
OAT
MAT
Zone Heating
Space Temp
-
-
-50.0 - 250°F
Unocc Htg Spt
55.0°F
1
0.0 - 99.0°F
UnocHtgDiff
3.0°F
1
1.0 - 10.0°F
Htg Ena
Off Amb
Off Alarm
Htg Status
-
-
Off None
Off Sw
Off Net
Off Man
McQuay OM-711-1
OAT Htg Lock
55.0°F
1
0.0 - 100.0°F
OAT Lock Diff
3.0°F
1
0.0 - 10.0°F
19
Table 5: Schedules menu (continued)
Disch Air
-
-
Clg Capacity
-
-
-50.0 - 250°F
0-100%
Eff Clg Spt
-
-
40.0 - 100.0°F
DAT Clg Spt
55.0°F
1
40.0 - 100.0°F
Clg Db
1.0°F
1
0.0 - 10°F
Min Clg Spt
55°F
1
40.0 - 100.0°F
Max Clg Spt
65°F
1
40.0 - 100.0°F
None
Discharge Cooling
Space
Return
Clg Reset
Air Flow
1
OAT
Ext mA
Ext V
Airflow
Waterside Economizer
Airside Economizer
Discharge Heating
Min Clg Spt@
90
1
Max Clg Spt@
40
1
0-100
0-100
Disch Air
-
-
-50.0 - 250°F
Econo Pos
-
-
0-100%
EWT
-
-
-50.0 - 250°F
EWT Diff
3.0°F
1
0.0 - 10.0°F
OA Damper Pos
-
-
0-100%
Eff Min OA Pos
-
-
0-100%
OA Ambient
-
-
Min OA Pos
10%
1
EconChgovr
Dry Bulb
1
Econ Chgovr T
60°F
1
EconChgovr Diff
1.0°F
1
0 - 10°F
Max Purge
60 min
1
0 - 240 min
OA Temp
-
-
-50.0 - 250°F
Disch Air
-
-
-50.0 - 250°F
Htg Capacity
-
-
0-100%
Eff Htg Spt
-
-
40 - 140°F
DAT Htg Spt
100.0°F
1
40 - 140°F
Htg Db
1.0°F
1
0 - 10°F
Min DAT Ctrl
Yes
1
Min Htg Spt
60°F
1
40 - 140°F
Max Htg Spt
120°F
1
40 - 140°F
Low
High
0 - 100%
Enthalpy
Dry Bulb
0.0 - 99.0°F
Yes
No
None
Space
Htg Reset
None
1
Return
OAT
Ext mA
Ext V
20
Min Htg Spt@
60
1
0-100
Max Htg Spt@
20
1
0-100
McQuay OM-711-1
Schedules
Menus in the Schedules category contain status and control
setpoint parameters that relate to scheduling the start stop of
the unit. Table 6 on page 22 lists all menus and items in the
Schedules group or category. The “Range” column in the
table lists all possible values for each item. The factory
settings for the adjustable parameters are shown in the
“Factory Default Value” column. The following are brief
descriptions of the Schedules category menus and items. For
detailed information regarding scheduling the start/stop of
the unit, refer to “Auto/Manual Operation” on page 40 and
“Scheduling” on page 44.
Daily Schedule
The Daily Schedule menu contains parameters for setting the
daily internal start stop schedule for the unit.
Mon. Mon= is an adjustable item that sets one start and one
stop time for Monday.
Hol 1 through Hol 16. Hol 1= through Hol 16= are
adjustable items that are used to define up to 16 holiday
periods throughout the calendar year.
Optimal Start
The Optimal Start menu contains parameters for adjusting
the action of the optimal start function. For detailed
information regarding the optimal start function, refer to
“Optimal Start” on page 45.
Space Temp. Space Temp= is a status only item that
displays the current space (or zone) temperature reading
from the optional unit space air temperature sensor input.
Refer to “Zone (Space) Temperature Sensor” on page 52.
Note: If an optional space temperature sensor is not
installed, the Space Sensor= item in the Unit
Configuration menu should be set to “No” to disable
the alarm function associated with an open circuit at
the space temperature sensor input.
Tue. Tue= is an adjustable item that sets one start and one
stop time for Tuesday.
Optimal Start. Optimal Start= is an adjustable item used to
Wed. Wed= is an adjustable item that sets one start and one
turn the optimal start function on and off.
stop time for Wednesday.
time for Friday.
Auto Update. Auto Update= is an adjustable item used to
turn on and off a feature included in the optimal start
function where the controller “learns” and updates the
optimal start parameters automatically based on previous
results.
Sat. Sat= is an adjustable item that sets one start and one
Htg Rate. Htg Rate= is an adjustable item used by the
stop time for Saturday.
controller in determining the amount of time before
occupancy to start when the Optimal Start= parameter is set
to “On.”
Thu. Thu= is an adjustable item that sets one start and one
stop time for Thursday.
Fri. Fri= is an adjustable item that sets one start and one stop
Sun. Sun= is an adjustable item that sets one start and one
stop time for Sunday.
Hol. Hol= is an adjustable item that sets one start and one
Htg OAT. Htg OAT= is an adjustable item used by the
stop time for Holidays.
One Event Schedule
controller in determining the amount of time before
occupancy to start when the Optimal Start= parameter is set
to “On.”
The One Event Schedule menu contains parameters for
setting a beginning and ending date and time for a one event
schedule that override the daily internal start stop schedule
for that period.
Htg Zero OAT. Htg Zero OAT= is an adjustable item used by
the controller in determining the amount of time before
occupancy to start when the Optimal Start= parameter is set
to “On.”
Beg. Beg= is an adjustable item that sets the start date and
time for a one event schedule that overrides the daily internal
start stop schedule for the period defined by it and the End=
parameter.
Clg Rate. Clg Rate= is an adjustable item used by the
controller in determining the amount of time before
occupancy to start when the Optimal Start= parameter is set
to “On.”
End. End= is an adjustable item that sets the stop date and
time for a one event schedule that overrides the daily internal
start stop schedule for the period defined by it and the Beg=
parameter.
Holiday Schedule
The Holiday Schedule menu contains parameters for
defining up to 16 holiday periods throughout the year. A
beginning and ending date is assigned to each holiday
period. On each day of the holiday period, the holiday
schedule entered in the Daily Schedules menu is used.
McQuay OM-711-1
Clg OAT. Clg OAT= is an adjustable item used by the
controller in determining the amount of time before
occupancy to start when the Optimal Start= parameter is set
to “On.”
Clg Zero OAT. Clg Zero OAT= is an adjustable item used by
the controller in determining the amount of time before
occupancy to start when the Optimal Start= parameter is set
to “On.”
21
Table 6: Schedules menus
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
00
1
00 - 23
00
2
00 - 59
00
3
00 - 23
00
4
00 - 59
Tue
Same As Monday
Same As Monday
Same As Monday
Wed
Same As Monday
Same As Monday
Same As Monday
Thu
Same As Monday
Same As Monday
Same As Monday
Fri
Same As Monday
Same As Monday
Same As Monday
Sat
Same As Monday
Same As Monday
Same As Monday
Sun
Same As Monday
Same As Monday
Same As Monday
Hol
Same As Monday
Same As Monday
Same As Monday
1
Jan-Dec
2
01-31
3
00-23
Mon
Daily Schedule
Beg
N/A
One Event Schedule
End
Holiday Schedule
Optimal Start
22
N/A
4
00-59
1
Jan-Dec
2
01-31
3
00-23
4
00-59
1
Jan-Dec
2
01-31
3
Jan-Dec
Hol 1
N/A-N/A
4
01-31
Hol 2
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 3
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 4
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 5
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 6
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 7
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 8
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 9
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 10
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 11
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 12
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 13
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 14
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 15
Same As Hol 1
Same As Hol 1
Same As Hol 1
Hol 16
Same As Hol 1
Same As Hol 1
Same As Hol 1
Space Temp
-
-
-50 - 250.0 °F
Optimal Start
No
1
Auto Update
Yes
1
Htg Rate
0.4 °F/min
1
Htg OAT
35 °F
1
0 - 255 °F
Htg Zero OAT
0 °F
1
-40 - 60 °F
Clg Rate
0.4 °F/min
1
0-1 °F/min
Clg OAT
85 °F
1
0 - 255 °F
Clg Zero OAT
100 °F
1
60 - 140 °F
No
Yes
No
Yes
0-1 °F/min
McQuay OM-711-1
Setup/Service
Menus in the Setup/Service category contain status and
control parameters that relate to the setup and service of the
unit. Parameters in these menus are generally the type that
are set at the factory. They might be adjusted when the
equipment is started up, but generally do not require further
adjustment. Table 7 on page 30 lists all menus and items in
the Setup/Service group or category. The “Range” column in
the table lists all possible values for each item. The factory
settings for the adjustable parameters are shown in the
“Factory Default Value” column. The following are brief
descriptions of the Setup/Service category menus and items.
Unit Configuration
The Unit Configuration menu contains parameters that
define various basic unit configuration attributes.
AHU ID. AHU ID= is a status only item that identifies the
version of application software loaded into the unit main
control board (MCB) Refer to Table on page 93.
KP ID. KP ID= is a status only item that identifies the
version of the keypad object loaded into the unit main
control board (MCB).
Calibrate Mode. Calibrate Mode= is an adjustable item
used to place the unit into the Calib operating state. In this
state the unit is shut off and all the unit actuator feedback
signals are calibrated. The unit static pressure sensor input
signals are also zeroed during this state. For detailed
information regarding calibration, refer to “Calibrate Mode”
on page 51.
Space Sensor. Space Sensor= is an adjustable item used to
indicate whether or not an optional space air temperature
sensor is installed. Setting this parameter to “No” disables
the alarm function associated with an open circuit at the
space temperature sensor input. Also, if “No” is selected, the
Cntl Temp Src= parameter cannot be set to “Space” and the
Clg Reset= and the Htg Reset= parameters cannot be set to
“Space.” For more information regarding the optional space
temperature sensor, refer to “Zone (Space) Temperature
Sensor” on page 52.
MAT Sensor. MAT Sensor= is an adjustable item used to
indicate whether or not a mixed air temperature sensor is
installed. Setting this parameter to “No” disables the alarm
function associated with an open circuit at the mixed air
temperature sensor input. Also, if “No” is selected, the Cntl
Temp Src= parameter cannot be set to “MAT.”
OAT Sensor. OAT Sensor= is an adjustable item used to
indicate whether or not an outside air temperature sensor is
installed. Setting this parameter to “No” disables the alarm
function associated with an open circuit at the outside air
temperature sensor input. Also, if “No” is selected, the Cntl
Temp Src= parameter cannot be set to “OAT.”
Return Sensor. Return Sensor = is an adjustable item used
to indicate whether or not a return air temperature sensor is
installed. Setting this parameter to “No” disables the alarm
McQuay OM-711-1
function associated with an open circuit at the return air
temperature sensor input. Also, if “No” is selected, the Crtl
Temp Src= parameter cannot be set to “Return.”
2nd P Sensor. 2nd P Sensor= is an adjustable item used to
indicate whether or not an optional second static pressure
sensor is installed in a VAV unit. When this parameter is set to
“Duct,” the controller assumes there is a second duct static
pressure sensor installed and displays and controls the unit
discharge inlet vanes or AFD based on the lower of the two
inputs. When this parameter is set to “Bldg,” the controller
assumes there is a second static pressure sensor installed and
that it is a building static pressure sensor. In this case the unit
supply inlet vanes or AFD are controlled to maintain the
building pressure at a building pressure setpoint. When this
parameter is set to “None,” the controller assumes there is not
a second static pressure sensor installed and ignores the
associated analog input. For detailed information regarding
discharge fan capacity control, refer to “Discharge Fan
Capacity Control” on page 81.
DF CapCtrl. DF CapCtrl= is an adjustable item used to
select the type of discharge fan airflow control to be used on
a VAV unit. If this parameter is set to “DuctPres,” then the
discharge fan airflow is controlled to maintain the duct static
pressure at the duct static pressure setpoint. If this parameter
is set to “Position,” then the discharge fan airflow is
controlled to an inlet vane position or AFD speed setpoint set
via a network signal. For detailed information regarding
discharge fan capacity control, refer to “Discharge Fan
Capacity Control” on page 81.
Flush Econo. Flush Econo = is an adjustable item that
allows the waterside economizer valve to be open during
start-up. Setting this parameter to “Yes” enables this
function.
Remote DF Cap. Remote DF Cap= is an adjustable item
that adjusts the discharge air vane position or AFD speed
when the DF Cap Ctrl= parameter is set to “Position.” This
parameter can be manually adjusted or set via a network
signal.
Eng Units. Eng Units= is an adjustable item used to select
the system of engineering units used for displaying data on
the keypad. If this parameter is set to “English,” the keypad
data is displayed in inch-pound (I-P) units of measurement.
If this parameter is set to “SI Canada,” the keypad data is
displayed in the International System of Units (SI) used in
Canada. If this parameter is set to “SI Europe,” the keypad
data is displayed in the International System of Units (SI)
used in Europe.
Passwords
The Passwords menu contains parameters that relate to the
keypad passwords. For detailed information regarding
passwords, refer to “Password Protection” on page 6.
Timeout. Timeout= is an adjustable item used to set the
duration of a timer, which is set whenever the keypad
password is entered. Once the password is entered, setpoints
23
can be changed and alarms can be cleared without reentering
the password, for the duration of the timer.
hours before rolling over. This status item can be reset or
adjusted manually from the keypad.
Clear Alarm. Clear Alarm= is an adjustable item used to set
which password level is required to allow the user to clear
alarms. If this parameter is set to “Lvl 1” then at least the
level 1 password must be entered to allow alarms to be
cleared. If this parameter is set to “Lvl 2” then the level 2
password must be entered to allow alarms to be cleared. If
this parameter is set to “None” then a password entry is not
required to allow alarms to be cleared.
Heating Op. HeatingOp= is a status item that indicates the
Operating Hours
The Operating Hours menu contains items that indicate how
many hours the fans, cooling and heating, override and
energy recover have been operating. This information can be
used for scheduling maintenance and monitoring unit
operation.
Dish Fan. Disch Fan= is a status item that indicates the
hours that the units fan has operated. This value accumulates
to 50,000 hours before rolling over. This status item can be
reset or adjusted manually from the keypad.
Mech Cool. Mech Cool= is a status item that indicates the
hours that the unit mechanical cooling has operated. This
value accumulates to 50,000 hours before rolling over. This
status item can be reset or adjusted manually from the
keypad.
Comp 1. Comp 1= is a status item that indicates the hours
compressor #1 has operated on units equipped with
compressorized cooling. This value accumulates to 50,000
hours before rolling over. This status item can be reset or
adjusted manually from the keypad.
Comp 2. Comp 2= is a status item that indicates the hours
compressor #2 has operated on units equipped with
compressorized cooling. This value accumulates to 50,000
hours before rolling over. This status item can be reset or
adjusted manually from the keypad.
Comp 3. Comp 3= is a status item that indicates the hours
compressor #3 has operated on units equipped with
compressorized cooling. This value accumulates to 50,000
hours before rolling over. This status item can be reset or
adjusted manually from the keypad.
Comp 4. Comp 4= is a status item that indicates the hours
hours that the unit heating has operated. This value
accumulates to 50,000 hours before rolling over. This status
item can be reset or adjusted manually from the keypad.
Econo Op. EconoOp= is a status item that indicates the
hours that the unit has been in the Econo operating state.
This value accumulates to 50,000 hours before rolling over.
This status item can be reset or adjusted manually from the
keypad.
Tenant Ovrd. TenantOvrd= is a status item that indicates the
hours that the unit has operated in the schedule tenant
override mode of operation. This value accumulates to
50,000 hours before rolling over. This status item can be
reset or adjusted manually from the keypad.
Timer Settings
The Timer Settings menu contains several parameters for
setting the controller process timers. For detailed
information regarding these timers, refer to “Control Timer
Settings” on page 53.
Service. Service= is an adjustable item that sets a time
period during which many of the controller process timers,
such as the cooling and heating interstage timers, are sped
up. Once this parameter is set to a none-zero time value the
fast timers are used until this timer expires.
Recirculate. Recirculate= is an adjustable item that defines
the duration of the Recirc operating state.
Low DAT. Low DAT= is an adjustable item that sets the
duration of a time period after unit start up during which the
Lo Disch Tmp fault ignored.
Max MWU. Max MWU= is an adjustable item that sets a
maximum duration for the MWU (morning warm up)
operating state.
Tenant Ovrd. TenantOvrd= is an adjustable item that sets
the time period during which the unit operates each time the
tenant override button on the optional space temperature
sensor is pressed or the Occ Mode= parameter is switched to
“Tenant Override.” For detailed information regarding tenant
override operation refer to “Tenant Override” on page 43.
compressor #4 has operated on units equipped with
compressorized cooling. This value accumulates to 50,000
hours before rolling over. This status item can be reset or
adjusted manually from the keypad.
Start Init. Start Init= is an adjustable item that sets the
Comp 5. Comp 5= is a status item that indicates the hours
Post Heat. Post Heat= is an adjustable item that sets the
compressor #5 has operated on units equipped with
compressorized cooling. This value accumulates to 50,000
hours before rolling over. This status item can be reset or
adjusted manually from the keypad.
duration of the “post heat” function on VAV units. For
detailed information regarding “post heat” operation, refer to
“Post Heat Operation” on page 83
Comp 6. Comp 6= is a status item that indicates the hours
compressor #6 has operated on units equipped with
compressorized cooling. This value accumulates to 50,000
24
duration of the Startup operating state.
Bypass Valve. Bypass Valve = is an adjustable item that sets
the duration of the Bypass valve timer. For detailed
information the Bypass Valve timer, refer to “Control Timer
Settings” on page 53.
McQuay OM-711-1
Airflow. Airflow = is an adjustable item that sets the duration
of the airflow timer. For detailed information the airflow
timer, refer to “Control Timer Settings” on page 53.
Comp Delay. Comp Delay = is an adjustable item that sets
the duration of the compressor delay timer when unit is
configured with head pressure control. For detailed
information regarding the compressor delay timer, refer to
“Control Timer Settings” on page 53.
LP Alm Delay. LP Alm Delay= is an adjustable item, that
sets the duration of the ignore low pressure switch timer. A
low pressure alarm can not occur until this timer has timed
out.
Time/Date
The Time/Date menu contains three parameters for setting
the controller current date and time. For detailed information
regarding these parameters, refer to “Setting Controller Date
and Time” on page 44.
Time. Time= is an adjustable item that sets the controller
current time.
The time must be entered and is displayed in “military” time
(hh:mm:ss).
Day. Day= is a status only item that displays the current day
of the week based on the value of the Date= parameter.
Date. Date= is an adjustable item that sets the current date
including date, month and year.
Duct Static P Setup
The Duct Static P Setup menu contains several adjustable
parameters that affect the response timing for the PID
control action used by the controller when modulating the
discharge air fan inlet vanes or AFD to maintain duct static
pressure on VAV units. For detailed information regarding
these control parameters, refer to “MicroTech II DDC
Features” on page 90.
DSP Propbd. DSP Propbd= is an adjustable item that sets
the “proportional band” used in the PID control function that
modulates the discharge air fan inlet vanes or AFD. In
general, increasing this value has a slowing effect and
decreasing this value has a speeding effect on the control of
the discharge fan inlet vanes or AFD.
DSP IntTime. DSP IntTime= is an adjustable item that
varies the “integral time” used in the PID control function
that modulates the discharge air fan inlet vanes or AFD. In
general, increasing this value has a slowing effect and
decreasing this value has a speeding effect on the control of
the discharge fan inlet vanes or AFD.
DSP Period. DSP Period= is an adjustable item that sets the
“sampling period” used in the PID control function that
modulates the discharge air fan inlet vanes or AFD. In
general, increasing this value has a slowing effect and
decreasing this value has a speeding effect on the control of
the discharge fan inlet vanes or AFD.
McQuay OM-711-1
PRAC. PRAC= is an adjustable item used to automatically
tune the duct static pressure control PID parameters. In
general, leave this parameter in the “No” setting. Use it only
if there are problems with duct static pressure control using
the default PID parameters. For detailed information
regarding the PRAC function, see “MicroTech II DDC
Features” on page 90.
Bldg Static P Setup
The Bldg Static P Setup menu contains several adjustable
parameters that affect the response timing for the PID
control action used by the controller when modulating the
supply air fan inlet vanes or AFD to maintain building static
pressure. These parameters apply only when the DF
CapCtrl= parameter in the Unit Configuration menu is set to
“BldgPres.” For detailed information regarding these control
parameters, refer to “MicroTech II DDC Features” on page
90.
BSP Propbd. BSP Propbd= is an adjustable item that sets
the “proportional band” used in the PID control function that
modulates the supply air fan inlet vanes or AFD in response
to building static pressure. In general, increasing this value
has a slowing effect and decreasing this value has a speeding
effect on the control of the supply air fan inlet vanes or AFD.
BSP IntTime. BSP IntTime= is an adjustable item that varies
the “integral time” used in the PID control function that
modulates the supply air fan inlet vanes or AFD in response
to building static pressure. In general, increasing this value
has a slowing effect and decreasing this value has a speeding
effect on the control of the supply air fan inlet vanes or AFD.
BSP Period. BSP Period= is an adjustable item that sets the
“sampling period” used in the PID control function that
modulates the supply air fan inlet vanes or AFD. In general,
increasing this value has a slowing effect and decreasing this
value has a speeding effect on the control of the supply air
fan inlet vanes or AFD.
PRAC. PRAC= is an adjustable item used to automatically
tune the building static pressure PID parameters. In general,
leave this parameter in the “No” setting. Use it only if there
are problems with building static pressure control using the
default PID parameters. For detailed information regarding
the PRAC function, refer to “MicroTech II DDC Features”
on page 90.
Head Pressure Setup
WRV Db. WRV Db= is an adjustable item that sets a
deadband around the Head Pressure Setpoint= parameter.
WRV Propbd. WRV Propbd= is an adjustable item that sets
the “proportional band” used in the PID control function that
modulates the water-regulating valve. In general, increasing
this value has a slowing effect and decreasing this value has
a speeding effect on the control of the water-regulating
valve.
WRV IntTime. WRV IntTime= is an adjustable item that
varies the “integral time” used in the PID control function
25
that modulates the water-regulating valve. In general,
increasing this value has a slowing effect and decreasing this
value has a speeding effect on the control of the waterregulating valve.
WRV Period. WRV Period= is an adjustable item that sets
the “sampling period” used in the PID control function that
modulates the water-regulating valve. In general, increasing
the value has a slowing effect and decreasing this value has a
speeding effect on the control of the water-regulating valve.
the Eff Clg Spt= value than before the change. For detailed
information regarding the two discharge air temperature
control methods, refer to “Temperature Control” on page 62.
Clg, Stage Time. Clg. Stage Time= is an adjustable item
used to set the minimum time between consecutive cooling
staging actions.
Chilled Water Setup
tune the WRV control PID parameters. In general, leave this
parameter in the “No” setting. Use it only if there are
problems with WRV control using the default PID
parameters. For detailed information regarding the PRAC
function, see “MicroTech II DDC Features” on page 90.
The Chilled Water Setup menu contains several adjustable
parameters that affect the response timing for the PID
control action used by the controller when modulating the
chilled water valve to maintain the discharge cooling
setpoint. For detailed information regarding these control
parameters, refer to “MicroTech II DDC Features” on page
90.
Compressor Setup
Clg Propbd. Clg Propbd= is an adjustable item that sets the
PRAC. PRAC= is an adjustable item used to automatically
The Compressor Setup menu contains several adjustable
parameters than affect the compressor staging on units
equipped with compressorized cooling. For detailed
information regarding compressorized cooling staging
operation, refer to“Cooling: Multistage” on page 67.
Compressor 1. Compressor 1 = is an adjustable item that
allows the compressor to be enabled or disabled. Setting this
parameter to “Disable” prevents the compressor from
operating.
Compressor 2. Compressor 2 = is an adjustable item that
allows the compressor to be enabled or disabled. Setting this
parameter to “Disable” prevents the compressor from
operating.
Compressor 3. Compressor 3 = is an adjustable item that
allows the compressor to be enabled or disabled. Setting this
parameter to “Disable” prevents the compressor from
operating.
Compressor 4. Compressor 4 = is an adjustable item that
allows the compressor to be enabled or disabled. Setting this
parameter to “Disable” prevents the compressor from
operating.
Compressor 5. Compressor 5 = is an adjustable item that
allows the compressor to be enabled or disabled. Setting this
parameter to “Disable” prevents the compressor from
operating.
Compressor 6. Compressor 6 = is an adjustable item that
allows the compressor to be enabled or disabled. Setting this
parameter to “Disable” prevents the compressor from
operating.
Clg Method. Clg Method= is an adjustable item used to
select the discharge temperature control method to be used
during cooling operation. When this parameter is set to
“Average,” cooling is staged up and down to maintain the
average discharge temperature over time at the Eff Clg Spt=
value in the Discharge Cooling menu. When this parameter
is set to “Nearest,” cooling is staged up and down so that a
change causes the discharge air temperature to be nearer to
26
“proportional band” used in the PID control function that
modulates the chilled water valve to maintain the discharge
air temperature. In general, increasing this value has a
slowing effect and decreasing this value has a speeding
effect on the control of the chilled water valve.
Clg IntTime. Clg IntTime= is an adjustable item that sets the
“integral time” used in the PID control function that
modulates the chilled water valve to maintain the discharge
air temperature. In general, increasing this value has a
slowing effect and decreasing this value has a speeding
effect on the control of the chilled water valve.
Clg Period. Clg Period= is an adjustable item that sets the
“sampling period” used in the PID control function that
modulates the chilled water valve to maintain the discharge
air temperature. In general, increasing this value has a
slowing effect and decreasing this value has a speeding
effect on the control of the chilled water valve.
Clg Stage Time. Clg Stage Time= is an adjustable item used
to set a minimum cooling time period. Once a unit enters the
Cooling operating state, the chilled water valve must be
closed for this time period before the unit leaves the Cooling
operating state.
PRAC. PRAC= is an adjustable item used to automatically
tune the chilled water valve control PID parameters. In
general, leave this parameter in the “No” setting. Use it only
if there are problems with chilled water valve control using
the default PID parameters. For detailed information
regarding the PRAC function, see “MicroTech II DDC
Features” on page 90.
Economizer Setup
The Economizer Setup menu contains several adjustable
parameters that affect the response timing for the PID
control action used by the controller when modulating the
economizer dampers or valve to maintain the discharge
cooling setpoint. For detailed information regarding these
control parameters, refer to “MicroTech II DDC Features”
on page 90.
McQuay OM-711-1
Clg Propbd. Clg Propbd= is an adjustable item that sets the
“proportional band” used in the PID control function that
modulates the economizer dampers or valve to maintain the
discharge air temperature. In general, increasing this value
has a slowing effect and decreasing this value has a speeding
effect on the control of the dampers.
Clg IntTime. Clg IntTime= is an adjustable item that sets the
“integral time” used in the PID control function that
modulates economizer dampers or valve to maintain the
discharge air temperature. In general, increasing this value
has a slowing effect and decreasing this value has a speeding
effect on the control of the dampers.
Clg Period. Clg Period= is an adjustable item that sets the
“sampling period” used in the PID control function that modulates
economizer dampers or valve to maintain the discharge air
temperature. In general, increasing this value has a slowing effect
and decreasing this value has a speeding effect on the control of the
dampers.
PRAC. PRAC= is an adjustable item used to automatically
tune the economizer control PID parameters. In general,
leave this parameter in the “No” setting. Use it only if there
are problems with economizer control using the default PID
parameters. For detailed information regarding the PRAC
function, refer to “MicroTech II DDC Features” on page 90.
PID control parameter, refer to “MicroTech II DDC
Features” on page 90.
PRAC. PRAC= is an adjustable item used to automatically
tune the heating valve control PID parameters. In general,
leave this parameter in the “No” setting. Use it only if there
are problems with heating valve control using the default
PID parameters. For detailed information regarding the
PRAC function, refer to “MicroTech II DDC Features” on
page 90.
Manual Control
The Manual Control menu contains parameters used to
control the outputs from the controller (MCB) in a manual
mode. This can be used to test the operation of the various
devices controlled by the outputs. For detailed information
regarding manual operation, refer to “Manual Output
Control” on page 55.
Manual Control. Manual Control= is an adjustable item
used to turn the manual control mode of operation on and
off. When this parameter is set to “No” the unit operates
normally. When this parameter is set to “Yes” normal control
of the control outputs is overridden and the condition of each
output is defined by setting the remaining items within the
Manual Control menu.
Heating Setup
Discharge Fan. Discharge Fan= is an adjustable item used
to manually turn the discharge air fan on and off.
The Heating Setup menu contains several adjustable
parameters that affect the control action used by the
controller to modulate the heating control actuator to
maintain the discharge heating setpoint.
Fan Operation. Fan Operation= is an adjustable item used
to manually turn the Fan Operation Output (MCB-BO3) on
and off.
Htg Stage Time. Htg Stage Time= is an adjustable item used
Alarm. Alarm= is an adjustable item used to manually turn
the Remote Alarm Output (MCB-BO4) on and off.
to set a minimum time period between heating staging
actions.
Htg Propbd. Htg Propbd = is an adjustable item that sets the
“proportional band” used in the PID control function that
modulates the heating valve to maintain the discharge air
temperature. In general, increasing this value has a slowing
effect and decreasing this value has a speeding effect on the
heating control actuator. For detailed information on this
PID control parameter, refer to “MicroTech II DDC
Features” on page 90.
Htg IntTime. Htg IntTime = is an adjustable item that sets the
“integral time” used in the PID control function that
modulates the heating valve to maintain the discharge air
temperature. In general, increasing this value has a slowing
effect and decreasing this value has a speeding effect on the
heating control actuator. For detailed information on this
PID control parameter, refer to “MicroTech II DDC
Features” on page 90.
Htg Period. Htg Period = is an adjustable item that sets the
“sampling period” used in the PID control function that
modulates the heating valve to maintain the discharge air
temperature. In general, increasing this value has a slowing
effect and decreasing this value has a speeding effect on the
heating control actuator. For detailed information on this
McQuay OM-711-1
Economizer. Economizer= is an adjustable item used to
manually drive the waterside or airside actuator open and
closed.
Bypass Valve. Bypass Valve = is an adjustable item used to
manually drive the bypass valve open and closed.
Water Reg Vlv. Water Reg Vlv = is an adjustable item used
to manually drive the water regulating valve open and
closed.
OA Damper. OA Damper = is an adjustable item used to
manually drive the outside air damper open and closed.
Mod Cooling. Mod Cooling= is an adjustable item used to
manually drive the modulating cooling valve open and
closed.
Mod Heating. Mod Heating= is an adjustable item used to
manually drive the modulating heating valve open and
closed.
VAV Output. VAV Output= is an adjustable item used to
manually turn the VAV Box Output (MCB-BO12) on and
off.
Disch Vanes. Disch Vanes= is an adjustable item used to
manually drive the discharge air fan inlet vanes open and
closed.
27
Disch AFD. Disch AFD= is an adjustable item used to
manually increase and decrease the discharge air fan AFD
speed.
Alarm Out Faults
The Alarm Out Faults menu contains parameters for
determining the action of the Remote Alarm Output (MCBBO4) when “fault” alarms occur. The Remote Alarm Output
is on continuously when there are no active alarms within the
controller. Each alarm can be set up to cause the Remote
Alarm Output to turn off, blink quickly, blink slowly or
remain on continuously when the alarm occurs. For detailed
information on configuring the Remote Alarm Output, refer
to“Configuring Remote Alarm Output” on page 51.
Freeze. Freeze= is an adjustable item used to determine the
action of the Remote Alarm Output when the Freeze fault
occurs.
Smoke. Smoke= is an adjustable item used to determine the
action of the Remote Alarm Output when the Smoke fault
occurs.
MAT Sensor. MAT Sensor = is an adjustable item used to
determine the action of the Remote Alarm Output when the
MAT Sensor fault occurs.
OAT Sensor. OAT Sensor= is an adjustable item used to
determine the action of the Remote Alarm Output when the
OAT Sensor fault occurs.
Space Sensor. Space Sensor= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Space Sensor fault occurs.
Return Sensor. Return Sensor= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Return Sensor fault occurs.
Disch Sensor. Disch Sensor= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Disch Sensor fault occurs.
Alarm Out Problems
The Alarm Out Problems menu contains parameters for
determining the action of the Remote Alarm Output (MCBBO4) when “problem” alarms occur. The Remote Alarm
Output is on continuously when there are no active alarms
within the controller. Each alarm can be set up to cause the
Remote Alarm Output to turn off, blink quickly, blink slowly
or remain on continuously when the alarm occurs. For
detailed information regarding configuring the Remote
Alarm Output, refer to “Configuring Remote Alarm Output”
on page 51.
Freeze. Freeze= is an adjustable item used to determine the
action of the Remote Alarm Output when the Freeze
problem occurs.
MAT Sensor. MAT Sensor = is an adjustable item used to
determine the action of the Remote Alarm Output when the
MAT Sensor Problem occurs.
EWT Sensor. EWT Sensor = is an adjustable item used to
determine the action of the Remote Alarm Output when the
EWT Sensor Problem occurs.
OAT Sensor. OAT Sensor= is an adjustable item used to
determine the action of the Remote Alarm Output when the
OAT Sensor problem occurs.
Space Sensor. Space Sensor= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Space Sensor problem occurs.
Return Sensor. Return Sensor= is an adjustable item used
to determine the action of the Remote Alarm Output when
the Return Sensor problem occurs.
Low Airflow. Low Airflow= is an adjustable item used to
determine the action of the Remote Alarm Output when the Low
Airflow problem occurs.
Heat Fail. Heat Fail= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Heat Fail problem occurs.
Duct Hi Limit. Duct Hi Limit= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Duct Hi Limit fault occurs.
Fan Retry. Fan Retry= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Fan Retry problem occurs.
Hi Return Tmp. Hi Return Tmp= is an adjustable item used
High Pres Ckt 1. High Pres 1= is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
to determine the action of the Remote Alarm Output when
the Hi Return Tmp fault occurs.
Hi Disch Tmp. Hi Disch Tmp= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Hi Disch Tmp fault occurs.
High Pres Ckt 2. High Pres 2= is an adjustable item used to
Lo Disch Tmp. Lo Disch Tmp= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Lo Disch Tmp fault occurs.
High Pres Ckt 3. High Pres 3= is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Fan Fail. Fan Fail= is an adjustable item used to determine
High Pres Ckt 4. High Pres 4= is an adjustable item used to
the action of the Remote Alarm Output when the Fan Fail
fault occurs.
determine the action of the Remote Alarm Output when the
problem occurs.
• High Pres Ckt 5. High Pres 5= is an adjustable item used
to determine the action of the Remote Alarm Output when
the problem occurs.
OA Dmpr Stuck. OA Dmpr Stuck= is an adjustable item
used to determine the action of the Remote Alarm Output
when the OA Dmpr Stuck fault occurs
28
determine the action of the Remote Alarm Output when the
problem occurs.
McQuay OM-711-1
High Pres Ckt 6. High Pres 6= is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
CompB1 Comm Fail. CompB1 Comm Fail= is an adjustable
item used to determine the action of the Remote Alarm
Output when the CompB1 Comm Fail problem occurs.
Circ 1 Lo P/Frost. Circ 1 Lo P/Frost= is an adjustable item
used to determine the action of the Remote Alarm Output
when the problem occurs.
CompB2 Comm Fail. CompB2 Comm Fail= is an adjustable
item used to determine the action of the Remote Alarm
Output when the CompB2 Comm Fail problem occurs.
Circ 2 Lo P/Frost. Circ 2 Lo P/Frost = is an adjustable item
used to determine the action of the Remote Alarm Output
when the problem occurs.
Circ 3 Lo P/Frost. Circ 3 Lo P/Frost = is an adjustable item
used to determine the action of the Remote Alarm Output
when the problem occurs.
Circ 4 Lo P/Frost. Circ 4 Lo P/Frost = is an adjustable item
used to determine the action of the Remote Alarm Output
when the problem occurs.
Circ 5 Lo P/Frost. Circ 5 Lo P/Frost = is an adjustable item
used to determine the action of the Remote Alarm Output
when the problem occurs.
Circ 6 Lo P/Frost. Circ 6 Lo P/Frost = is an adjustable item
used to determine the action of the Remote Alarm Output
when the problem occurs.
No Water Flow. No Water Flow = is an adjustable item used
to determine the action of the Remote Alarm Output when
the problem occurs.
Comp 1 MP. Comp 1 MP= is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Comp 2 MP. Comp 2 MP = is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Comp 3 MP. Comp 3 MP = is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Comp 4 MP. Comp 4 MP = is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Comp 5 MP. Comp 5 MP = is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Comp 6 MP. Comp 6 MP = is an adjustable item used to
determine the action of the Remote Alarm Output when the
problem occurs.
Water Reg Vlv. Water Reg Vlv = is an adjustable item used
to determine the action of the Remote Alarm Output when
the Water Reg Vlv problem occurs.
CompB1 Clg Ena. Clg Ena= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Clg Ena problem occurs.
CompB2 Clg Ena. Clg Ena= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Clg Ena problem occurs.
McQuay OM-711-1
Alarm Out Warnings
The Alarm Out Warnings menu contains parameters for
determining the action of the Remote Alarm Output (MCBBO4) when “warning” alarms occur. The Remote Alarm
Output is on continuously when there are no active alarms
within the controller. Each alarm can be set up to cause the
Remote Alarm Output to turn off, blink quickly, blink slowly
or remain on continuously when the alarm occurs. For
detailed information regarding configuring the Remote
Alarm Output, refer to “Configuring Remote Alarm Output”
on page 51.
Econo Stuck. Econo Stuck = is an adjustable item used to
determine the action of the Remote Alarm Output when the
Econo Stuck warning occurs.
Airflow Switch. Airflow Switch= is an adjustable item used
to determine the action of the Remote Alarm Output when
the Airflow Switch warning occurs.
Dirty Filter. Dirty Filter= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Dirty Filter warning occurs.
CompB1 H/W. CompB1 H/W= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Ckt1 H/W warning occurs.
CompB2 H/W. CompB2 H/W= is an adjustable item used to
determine the action of the Remote Alarm Output when the
Ckt2 H/W warning occurs.
Alarm Limits
The Alarm Limits menu contains parameters for setting three
miscellaneous temperature alarm limits.
Hi Disch Alm. Hi Disch Alm= is an adjustable item that sets
a high discharge air temperature alarm limit. If the discharge
air temperature input exceeds this setting, the unit shuts
down completely on the Hi Disch Tmp fault.
Lo Disch Alm. Lo Disch Alm= is an adjustable item that sets
a low discharge air temperature alarm limit. If the discharge
air temperature input falls below this setting while
mechanical cooling is not operating, the unit shuts down
completely on the Lo Disch Tmp fault.
Hi Return Alm. Hi Return Alm= is an adjustable item that
sets a high return air temperature alarm limit. If the return air
temperature input exceeds this setting, the unit shuts down
completely on the Hi Return Tmp fault.
29
Table 7: Setup/services menus
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
AHU ID
-
-
xxxxxxxxxx
KeypadID
-
-
xxxxxxxxxx
Calibrate Mode
No
1
No
Yes
No
Space Sensor
Nos
1
Yes
No
MAT Sensor
Yes
1
Yes
No
OAT Sensor
No
1
Yes
No
RAT Sensor
Yes
1
Unit Configuration
Yes
None
2nd P Sensor
None
1
Duct
Bldg
DuctPres
DF CapCtrl
DuctPres
1
BldgPres
Position
No
Flush Econo
Yes
1
Yes
English
Eng Units
English
Timeout
15 min
SI Canada
SI Europe
1
2-60 min
None
Passwords
Clear Alarm
None
1
Lvl-1
Disch Fan
0
1
0-50000 hr
Mech Cool
0
1
0-50000 hr
Comp 1
0
1
0-50000 hr
Comp 2
0
1
0-50000 hr
Comp 3
0
1
0-50000 hr
Comp 4
0
1
0-50000 hr
Comp 5
0
1
0-50000 hr
Comp 6
0
1
0-50000 hr
Heating Op
0
1
0-50000 hr
Econo Op
0
1
0-50000 hr
Tnt Ovrd
0
1
0-50000 hr
Service
0 min
1
0 - 240 min
Recirculate
3 min
1
2 - 60 min
Low DAT
3 min
1
2 - 60 min
Max MWU
90 min
1
0 - 240 min
Tnt Ovrd
120 min
1
0 - 300 min
Start Init
180 sec
1
0 - 240 sec
Post Heat
0 min
1
0 - 3 min
Bypass Valve
300 sec
1
60 - 600 sec
Airflow
60 sec
1
0 - 300 sec
LP Alm Delay
45 sec
1
30 - 240 sec
Comp Delay
30 sec
1
30 - 180 sec
Lvl-2
Operating Hours
Timer Settings
30
McQuay OM-711-1
Table 7: Setup/services menus (continued)
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
hh
1
00 - 23
mm
2
00 - 59
ss
3
00 - 59
-
-
Mon - Sun
dt
1
01-31
mon
2
Jan - Dec
year
3
1999-2155
DSP Propbd
6.0 “WC
1
1-100“ WC
DSP IntTime
40 sec
1
0-3600 sec
1-3600 sec
Time
Time/Date
Day
Date
Duct Static P Setup
Bldg Static P Setup
Head Pressure Setup
Compressor Setup
Chilled Water Setup
Economizer Setup
Heating Setup
McQuay OM-711-1
DSP Period
10 sec
1
BSP Propbd
1.0 “WC
1
1-100 “WC
BSP IntTime
10 sec
1
0-3600 sec
BSP Period
5 sec
1
1-3600 sec
WRV DB
10 PSI
1
0 - 10 PSI
WRV Propband
40 PSI
1
0 - 100 PSI
WRV Int Time
30 sec
1
0 - 3600 sec
WRV Period
10 sec
1
1 - 3600 sec
Compressor 1
Enable
1
Compressor 2
Enable
1
Compressor 3
Enable
1
Compressor 4
Enable
1
Compressor 5
Enable
1
Compressor 6
Enable
1
Clg Method
Nearest
1
Clg Stage Time
5 Min
1
Clg Propbd
30 °F
1
1-100 °F
Clg IntTime
60 sec
1
0-3600 sec
Enable
Disable
Enable
Disable
Enable
Disable
Enable
Disable
Enable
Disable
Enable
Disable
Nearest
Average
5 - 60 min
Clg Period
30 sec
1
1-3600 sec
Clg Stage Time
5 min
1
5-60 min
Clg Propbd
30 °F
1
1-100 °F
Clg IntTime
60 sec
1
0-3600 sec
Clg Period
30 sec
1
1-3600 sec
Htg Stage Time
10 min
1
2-60 min
Htg Propbd
20 °F
1
1-100 °F
Htg IntTime
240 sec
1
0-3600 sec
Htg Period
10 sec
1
1-3600 sec
31
Table 7: Setup/services menus (continued)
Menu Name
Menu Item Name
Factory Default Value
Field Number
Manual Control
No
1
Discharge Fan
Off
1
Fan Operation
Off
1
Alarm
Normal
1
Economizer
Auto
1
Range
No
Yes
On
Off
On
Off
Alarm
Normal
Close
Auto
Open
Close
Bypass Valve
Auto
1
Auto
Open
Close
Water Reg Valve
Auto
1
Manual Control
Auto
Open
OA Damper
Close
1
Close
Open
Close
Mod Cooling
Auto
1
Auto
Open
Close
Mod Heating
Auto
1
Auto
Open
VAV Output
Heat
1
Heat
Cool
Close
Disch Vanes
Auto
1
Auto
Open
Slower
Disch VFD
Auto
1
Auto
Faster
On
Off
Freeze
Fast
1
Smoke
Fast
1
Same As Freeze
MAT Sensor
Fast
1
Same As Freeze
OAT Sensor
Fast
1
Same As Freeze
Space Sensor
Fast
1
Same As Freeze
Return Sensor
Fast
1
Same As Freeze
Disch Sensor
Fast
1
Same As Freeze
Duct Hi Limit
Fast
1
Same As Freeze
Hi Return Tmp
Fast
1
Same As Freeze
Hi Disch Tmp
Fast
1
Same As Freeze
Lo Disch Tmp
Fast
1
Same As Freeze
Fan Fail
Fast
1
Same As Freeze
OA Dmpr Stuck
Fast
1
Same As Freeze
Fast
Slow
Alarm Out Faults
32
McQuay OM-711-1
Table 7: Setup/services menus (continued)
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
On
Off
Freeze
Slow
1
MAT Sensor
Slow
1
Same As Freeze
EWT Sensor
Slow
1
Same As Freeze
OAT Sensor
Slow
1
Same As Freeze
Space Sensor
Slow
1
Same As Freeze
Return Sensor
Slow
1
Same As Freeze
Heat Fail
Slow
1
Same As Freeze
Low Airflow
Slow
1
Same As Freeze
Fan Retry
Slow
1
Same As Freeze
Hi Pres Ckt 1
Slow
1
Same As Freeze
Hi Pres Ckt 2
Slow
1
Same As Freeze
Hi Pres Ckt 3
Slow
1
Same As Freeze
Hi Pres Ckt 4
Slow
1
Same As Freeze
Hi Pres Ckt 5
Slow
1
Same As Freeze
Hi Pres Ckt 6
Slow
1
Same As Freeze
Circ 1 Lo P/Frost
Slow
1
Same As Freeze
Circ 2 Lo P/Frost
Slow
1
Same As Freeze
Circ 3 Lo P/Frost
Slow
1
Same As Freeze
Circ 4 Lo P/Frost
Slow
1
Same As Freeze
Circ 5 Lo P/Frost
Slow
1
Same As Freeze
Circ 6 Lo P/Frost
Slow
1
Same As Freeze
No Water Flow
Slow
1
Same As Freeze
Water Reg Vlv
Slow
1
Same As Freeze
Comp 1 MP Alm
Slow
1
Same As Freeze
Comp 2 MP Alm
Slow
1
Same As Freeze
Comp 3 MP Alm
Slow
1
Same As Freeze
Comp 4 MP Alm
Slow
1
Same As Freeze
Comp 5 MP Alm
Slow
1
Same As Freeze
Comp 6 MP Alm
Slow
1
Same As Freeze
CompB1 Clg Ena
Slow
1
Same As Freeze
CompB2 Clg Ena
Slow
1
Same As Freeze
CompB1 Comm Fail
Slow
1
Same As Freeze
CompB2 Comm Fail
Slow
1
Same As Freeze
Fast
Slow
Alarm Out Problems
On
Alarm Out Warning
Alarm Limits
McQuay OM-711-1
Off
Econo Stuck
Off
1
Airflow Switch
Off
1
Same As Econo Stuck
Fast
Slow
Dirty Filter
Off
1
Same As Econo Stuck
CompB1 H/W
Off
1
Same As Econo Stuck
CompB2 H/W
Off
1
Same As Econo Stuck
Hi Discharge Alm
170 °F
1
90 - 250 °F
Lo Discharge Alm
40 °F
1
20 - 50 °F
Hi Return Alm
120 °F
1
90 - 150 °F
33
Active Alarms
Active Alarm 3
Menus in the Active Alarms category contain alarm
information for up to 4 active alarms. Table 8 on page 35
lists all menus and items in the Active Alarms group or
category. The “Range” column in the table lists all possible
values for each item. The factory settings for the adjustable
parameters are shown in the “Factory Default Value”
column. The following are brief descriptions of the Active
Alarms category menus and items. For detailed information
regarding alarm handling, refer to “Alarm Monitoring” on
page 46 and “Alarm Control” on page 84.
The Active Alarm 3 menu provides details regarding the
third highest priority active alarm.
Alarm Name. Alarm Name= is a status only item that
identifies the name of Active Alarm 3.
Alarm Type. Alarm Type= is a status only item that
identifies the alarm type (fault, problem or warning) of
Active Alarm 3.
Alarm Date and Time. This is a status only item that
indicates the date and time of occurrence of Active Alarm 3.
Active Alarm 1
Active Alarm 4
The Active Alarm 1 menu provides details regarding the
highest priority active alarm.
The Active Alarm 4 menu provides details regarding the
fourth highest priority active alarm.
Alarm Name. Alarm Name= is a status only item that
identifies the name of Active Alarm 1.
Alarm Name. Alarm Name= is a status only item that
identifies the name of Active Alarm 4.
Alarm Type. Alarm Type= is a status only item that
Alarm Type. Alarm Type= is a status only item that
identifies the alarm type (fault, problem or warning) of
Active Alarm 1.
identifies the alarm type (fault, problem or warning) of
Active Alarm 4.
Alarm Date and Time. This is a status only item that
Alarm Date and Time. This is a status only item that
indicates the date and time of occurrence of Active Alarm 4
indicates the date and time of occurrence of Active Alarm 1.
Active Alarm 2
The Active Alarm 2 menu provides details regarding the
second highest priority active alarm.
Alarm Name. Alarm Name= is a status only item that
identifies the name of Active Alarm 2.
Alarm Type. Alarm Type= is a status only item that
identifies the alarm type (fault, problem or warning) of
Active Alarm 2.
Alarm Date and Time. This is a status only item that
indicates the date and time of occurrence of Active Alarm 2.
34
McQuay OM-711-1
Table 8: Active alarm menus
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
None
Freeze (Fault)
Smoke (Fault)
MAT Sensor (Fault)
OAT Sensor (Fault)
Space Sensor (Fault)
Return Sensor (Fault)
Disch Sensor (Fault)
Duct Hi Limit (Fault)
Hi Return Tmp (Fault)
Hi Disch Tmp (Fault)
Lo Disch Tmp (Fault)
Fan Fail (Fault)
Econo Stuck (Fault)
OA Dmpr Stuck (Fault)
Freeze (Problem)
MAT Sensor (Problem)
EWT Sensor (Problem)
OAT Sensor (Problem)
Space Sensor (Problem)
Return Sensor (Problem)
Low Air Flow (Problem)
Heat Fail (Problem)
Fan Retry (Problem)
Hi Pres Ckt 1 (Problem)
Hi Pres Ckt 2 (Problem)
Active Alarm 1
Alarm Name
-
-
Hi Pres Ckt 3 (Problem)
Hi Pres Ckt 4 (Problem)
Hi Pres Ckt 5 (Problem)
Hi Pres Ckt 6(Problem)
Circ 1Lo P/Frost (Problem)
Circ 2Lo P/Frost (Problem)
Circ 3Lo P/Frost (Problem)
Circ 4Lo P/Frost (Problem)
Circ 5Lo P/Frost (Problem)
Circ 6Lo P/Frost (Problem)
Water Reg Vlv (Problem)
No Water Flow (Problem)
Comp 1 MP Alm (Problem)
Comp 2 MP Alm (Problem)
Comp 3 MP Alm (Problem)
Comp 4 MP Alm (Problem)
Comp 5 MP Alm (Problem)
Comp 6 MP Alm (Problem)
CompB1 Clg Ena (Problem)
CompB2 Clg Ena (Problem)
CompB1 Comm Fail (Problem)
CompB2 Comm Fail (Problem)
OA Dmpr Stuck (Warning)
Econo Stuck (Warning)
Airflow Switch (Warning)
Dirty Filter (Warning)
CompB1 H/W (Warning)
CompB2 H/W (Warning)
McQuay OM-711-1
35
Table 8: Active alarm menus (continued)
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
Fault-Active
Alarm Type
-
-
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Problem-Active
Warning-Active
Active Alarm 2
Fault-Active
Alarm Type
-
-
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Problem- Active
Warning- Active
Active Alarm 3
Fault- Active
Alarm Type
-
-
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Problem- Active
Warning- Active
Active Alarm 4
Alarm Type
-
-
Alarm Date and Time
-
-
Fault- Active
Problem- Active
Warning- Active
36
dd-mmm-yy/hh:mm:ss
McQuay OM-711-1
Alarm Name. Alarm Name= is a status only item that
identifies the name of Previous Alarm 1.
Previous Alarms
Menus in the Previous Alarms category contain alarm
information for up to 4 previous alarms. Table 8 lists all
menus and items in the Previous Alarms group or category.
The “Range” column in the table lists all possible values for
each item. The factory settings for the adjustable parameters
are shown in the “Factory Default Value” column. The
following are brief descriptions of the Previous Alarms
category menus and items. For detailed information
regarding alarm handling, refer to “Alarm Monitoring” on
page 46 and “Alarm Control” on page 84.
Alarm Type. Alarm Type= is a status only item that
identifies the alarm type (fault, problem or warning) of
Previous Alarm 1.
Alarm Date and Time. This is a status only item that
indicates the date and time of occurrence of Previous Alarm
1.
Previous Alarm 2 through Previous Alarm 8
The Previous Alarm 2 through the Previous Alarm 8 menus
provide details regarding the second through eighth most
recently cleared previous alarm. The description of these
menus is identical to Previous Alarm 1.
Previous Alarm 1
The Previous Alarm 1 menu provides details regarding the
most recently cleared previous alarm.
Table 9: Previous alarm menus
Menu Name
Menu Item Name
Factory Default Value
Field Number
Range
Alarm Name
-
-
Same As Active Alm 1
-
Previous Alarm 1
Alarm Type
-
-
Fault- Clear
Problem- Clear
Warning- Clear
Alarm Date and Time
Previous Alarm 2
Previous Alarm 3
Previous Alarm 4
Previous Alarm 5
Previous Alarm 6
Previous Alarm 7
Previous Alarm 8
McQuay OM-711-1
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
Alarm Name
-
-
Same As Active Alm 1
Alarm Type
-
-
Same As Previous Alm 1
Alarm Date and Time
-
-
dd-mmm-yy/hh:mm:ss
37
Operator’s Guide
The following “Operator’s Guide” sections provide
information regarding the day-to-day operation of the
MicroTech II Vertical Self-Contained Unit Controller. Topics
covered are such common tasks as scheduling, displaying
and clearing alarms, and setting the controller for manual
operation. Programmable parameters that affect the
operation being described are listed at the beginning of each
applicable sub-section. The factory default values for these
parameters are shown in italic letters.
Clg Capacity
For detailed information regarding the control processes and
their programmable parameters, refer to “Description of
Operation” on page 57.
Htg Capacity
Determining Unit Status
The System menu includes several parameters that can be
used to determine the overall status of the unit. There are
five key items in this menu that summarize the current
operating condition of the unit. These are: UnitStatus=, Clg
Capacity=, Htg Capacity=, Clg Status=, and Htg Status=
and are described in the following sections.
UnitStatus
The UnitStatus= parameter in the System menu is very
useful because the item summarizes the overall operating
condition of the unit. Each of the possible conditions is
referred to as an “operating state.” The following are the
possible operating states displayed by the UnitStatus=
parameter.
• Off
• OffNet
• OffSw
• OffAlarm
• OffMan
• Calib
• Startup
• Recirc
• Fan Only
• Econo
• Cooling
• MWU
• Heating
• Min DAT
• UnocEcon
• UnocFanO
• UnocDAT
• UnocClg
• UnocHtg
• Man Ctrl
The unit makes transitions between these operating states as
conditions change. For detailed information regarding these
states, refer to“Operating States and Sequences” on page 57.
38
Clg Capacity= is a status item that indicates the percentage
of the unit maximum cooling capacity currently operating.
When the unit is equipped with chilled water cooling, 0100% is displayed as the cooling valve actuator strokes from
the closed to open position. When the unit is equipped with
compressorized cooling, the percentage value changes
incrementally based on the number operating cooling stages.
Htg Capacity= is a status item that indicates the percentage
of the unit maximum heating capacity currently operating.
When the unit is equipped with modulating heat, 0-100% is
displayed as the heating valve actuator strokes from the
closed to open position. When the unit is equipped with
staged heat, the percentage value changes incrementally
based on the number operating heating stages.
Clg Status
Clg Status= is a status item that indicates whether or not
cooling (economizer and/or mechanical) is currently
allowed. If cooling is disabled, the reason is indicated. The
following are descriptions of the various “Clg Status” states.
All Cooling Allowed
The Clg Status = parameter indicates “All Clg” when the
following conditions are true:
1. The unit is equipped with an economizer and either the
outdoor air (OA Ambient = parameter in the Economizer
Menu indicates “Low”) or entering water (EWT =
parameter is less than the MAT = parameter - EWT Diff
= parameter) is suitable for free cooling.
2. The entering water temperature is warm enough to
allow compressor operation (EWT = parameter in the
Temperatures menu is risen above the Min EWT =
setting plus the Min EWT Diff = parameter in the Zone
Cooling menu).
3. There is waterflow.
In this state the unit uses the economizer, mechanical
cooling, or both as required to maintain the cooling
setpoints.
Economizer Only
The Clg Status = parameter indicates “Econo” when the
following conditions are true:
1. The unit is equipped with an economizer and either the
outdoor air (OA Ambient = parameter in the Economizer
Menu indicates “Low”) or entering water (EWT =
parameter is greater than the MAT = parameter - EWT
Diff = parameter) is suitable for free cooling.
2. The entering water temperature is too cool to allow
compressor operation (EWT = parameter in the
McQuay OM-711-1
In this state the unit only uses the economizer to maintain the
cooling setpoints. Compressor operation is disabled.
TB2 in the main control panel are not made (binary input
MCB-BI3 is off). Refer to the “Manual Cooling and Heating
Enable/Disable” section of IM 710, MicroTech II Vertical
Self-Contained Unit Controller. All cooling is disabled
during the “Off Sw” state.
Mechanical Cooling Only
Off Man
The Clg Status = parameter indicates “Mech Clg” when both
of the following conditions are true:
The Clg Status= parameter indicates “Off Man” when
cooling is disabled via the Ctrl Mode= parameter in the
System menu. This occurs when the Ctrl Mode= parameter
is set to either “Heat Only” or “Fan Only.” All cooling is
disabled during the “Off Man” state.
Temperatures menu is below the Min EWT = setting in
the Zone Cooling menu).
3. There is waterflow.
1. The unit is not equipped with an economizer or either
the outdoor air (OA Ambient = parameter in the
Economizer Menu indicates “High”) or entering water
(EWT = parameter is greater than or equal to the MAT =
parameter - EWT Diff = parameter + 1° F) is not suitable
for free cooling.
2. There is waterflow.
In this state the unit only uses mechanical cooling to
maintain the cooling setpoints. Economizer operation is
disabled. If the unit is equipped with an airside economizer,
the outdoor air damper is maintained at the Eff Min OA Pos
= value.
Off Amb
The Clg Status= parameter indicates “Off Amb” when both
of the following conditions are true:
1. The unit is not equipped with an economizer or EWT or
outdoor air is not suitable for free cooling (OA
Ambient= parameter in the OA Damper menu indicates
“High”).
2. The unit is equipped with compressorized cooling and
the EWT is not suitable to allow compressor operation.
In this state both economizer and mechanical cooling
operation is disabled.
For applications that use an economizer, the “Off Amb” state
should not occur if the economizer changeover and
mechanical cooling lockout setpoints are adjusted properly.
If it does occur, it may indicate a problem with the enthalpy
control device, if economizer is airside.
Off Alm
The Clg Status= parameter indicates “Off Alm” when
cooling related alarms cause all cooling circuits to be
completely disabled and economizer operation is not
available. For detailed information regarding cooling alarms
and their effect on the unit operation, Refer to “Alarm
Control” on page 84. All cooling is disabled during the “Off
Alm” state.
Off No Flow
The Clg Status= parameter indicates “Off No Flow” when
no water is flowing to the unit and no airside economizer is
enabled.
Off Sw
The Clg Status= parameter indicates “Off Sw” when the
field cooling enable terminals 101 to 105 on terminal block
McQuay OM-711-1
Off Net
The Clg Status= parameter indicates “Off Net” when cooling
is disabled by a network signal affecting the Appl Mode=
parameter in the System menu. This is the case when the
Appl Mode= parameter is set to either “Heat Only” or “Fan
Only.” All cooling is disabled during the “Off Net” state.
Off None
The Clg Status= parameter indicates “Off None” when the
unit is equipped with no cooling of any kind.
Htg Status
Htg Status= is a status item that indicates whether or not
heating is currently allowed. If heating is disabled, the
reason is indicated. The following are descriptions of the
various “Htg Status” states.
Htg Ena
The Htg Status= parameter indicates “Htg Ena” when the
unit is equipped with some kind of heating and the outdoor
air is cool enough to allow heating operation and heat is not
disabled for some other reason. (OA Temp= parameter in the
Temperatures menu has dropped below the OATHtg Lock=
parameter by more that the OATLock Diff= setting in the
Zone Heating menu). In this state the unit uses the heat as
required to maintain the heating setpoints.
Off Amb
The Htg Status= parameter indicates “Off Amb” when the
unit is equipped with heat and the outdoor air is too warm to
allow heating operation (OA Temp= parameter in the
Temperatures menu has risen above the OATHtg Lock=
setting in the Zone Heating menu). In this state heating
operation is disabled.
Off Alm
The Htg Status= parameter indicates “Off Alm” when
heating related alarms cause all heating to be completely
disabled. For detailed information regarding heating alarms
and their effect on the unit operation, refer to “Alarm
Control” on page 84. All heating is disabled during the “Off
Alm” state.
39
Off Sw
The Htg Status= parameter indicates “Off Sw” when the
field heating enable terminals 101 to 106 on terminal block
TB2 in the main control panel are not made (binary input
MCB-BI4 off). Refer to the “Manual Cooling and Heating
Enable/Disable” section of IM 710, MicroTech II Vertical
Self-Contained Unit Controller. Heating is disabled during
the “Off Sw” state.
Off Man
The Htg Status= parameter indicates “Off Man” when heating is disabled via the Ctrl Mode= parameter in the System
menu. This occurs when the Ctrl Mode= parameter is set to
either “Cool Only” or “Fan Only.” Heating is disabled during the “Off Man” state.
Off Net
The Htg Status= parameter indicates “Off Net” when heating
is disabled by a network signal affecting the Appl Mode=
parameter in the System menu. This occurs when the Appl
Mode= parameter is set to either “Cool Only” or “Fan Only.”
Heating is disabled during the “Off Net” state.
Off None
The Htg Status= parameter indicates “Off None” when the
unit is equipped with no heating.
Auto/Manual Operation
The System menus includes two parameters that determine
whether cooling, heating, both cooling and heating or neither
are enabled during unit operation. These are the Ctrl Mode=
and Appl Mode= parameters. The Occupancy menu includes
five parameters that relate to the occupied/unoccupied
condition (start/stop) of the unit. These are the Occupancy=,
Occ Mode=, Occ Src=, Tenant Ovrd Time=, and Emerg
Override= parameters. These are described in the following
sections.
Power is connected to the unit controller and components
even when the unit is in any Off operating state. Before
servicing line voltage equipment or entering the unit,
remove power by turning off and tagging out the disconnect
switch.
Ctrl Mode
Table 10: Programmable parameters
Keypad/Display ID
Item Name
System
Ctrl Mode= Auto
Parameter Name
Control Mode
The unit cooling and heating can be set up for automatic
heat/cool, cool only, heat only, fan only, or network cool/heat
operation by setting the Control Mode. The unit can also be
40
Off
When the Control Mode is set to “Off,” the UnitStatus= is
“Off Man” and the unit is completely disabled.
Heat Cool
When the Control Mode is set to “Heat/Cool,” both cooling
and heating operation are allowed to operate as required to
maintain the cooling and heating setpoints.
Cool Only
When the Control Mode is set to “Cool Only,” cooling
operation is allowed to operate to maintain the cooling
setpoints. Heating operation is disabled (Htg Status= is “Off
Man”).
Heat Only
When the Control Mode is set to “Heat Only,” heating
operation is allowed to operate to maintain the heating
setpoints. Cooling operation is disabled (Clg Status= is “Off
Man”).
Fan Only
When the Control Mode is set to “Fan Only,” the fans are
allowed to operate but cooling and heating operation is
disabled (Clg Status= and Htg Status= are “Off Man”).
Auto
When the Control Mode is set to “Auto,” the heat/cool, cool
only, heat only, and fan only decision is determined by the
Appl Mode= parameter, which is set via a network signal as
described below. The Appl Mode= parameter has no effect
on unit operation unless the Control Mode is set to “Auto.”
Appl Mode
WARNING
Electric shock and moving machinery hazard. Can
cause personal injury or death.
Menu Name
manually disabled via the Control Mode. The following are
descriptions of the six available Control Mode selections.
Table 11: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
System
Appl Mode= Heat/Cool
Parameter Name
Application Mode
The unit heating and cooling can be set up for automatic
heat/cool, heat only, cool only or fan only operation based on
a network signal by setting the Ctrl Mode= parameter to
“Auto.” With the Ctrl Mode= parameter set to “Auto,” the
heat/cool, cool only, heat only, and fan only decision is
determined by the Application Mode. The Application Mode
is set by a network signal. The following sections describe
the five available Application Mode selections.
Note: The Application Mode has no effect on the unit
operation unless the Ctrl Mode= parameter is set to
“Auto.”
McQuay OM-711-1
Off
When the Application Mode is set to “Off,” the UnitStatus=
is “Off Net” and the unit is completely disabled, including
unoccupied heating (night set back) and unoccupied cooling
(night set up) operation.
Heat/Cool
When the Application Mode is set to “Heat/Cool,” both
cooling and heating operation are allowed to operate as
required to maintain the cooling and heating setpoints.
Cool Only
When the Application Mode is set to “Cool Only,” cooling
operation is allowed to operate as required to maintain the
cooling setpoints. Heating operation is disabled (Htg Status=
is “Off Net”).
Heat Only
When the Application Mode is set to “Heat Only,” heating
operation is allowed to operate as required to maintain the
heating setpoints. Cooling operation is disabled (Clg Status=
is “Off Net”).
Fan Only
When the Application Mode is set to “Fan Only,” the fans
are allowed to operate but cooling and heating operation is
disabled (Clg Status= and Htg Status= are “Off Net”).
Occupancy
Occupancy= is a status item that indicates whether the unit
is in an occupied or unoccupied mode of operation. The
following are descriptions of the various “Occupancy”
states.
Occ
The Occupancy= parameter indicates “Occ” when the unit is
in the occupied mode. In this mode, the unit generally starts
and runs continuously, cooling and heating as required to
maintain the occupied temperature setpoints.1 The unit is in
the occupied mode if any of the following conditions are
true:
1. A field supplied external time clock or a tenant override
switch signal in the form of a set of dry contacts is
closed across terminals 101 and 102 on the unit field
terminal block TB2 (binary input MCB-BI1 on). For
detailed information refer to “External Time Clock or
Tenant Override (Non-Timed)” in IM 710, MicroTech II
Vertical Self-Contained System Unit Controller.
2. The Occ Mode= parameter is set to “Occ.”
3. The Occ Mode= parameter is set to “Auto” and the unit
internal time clock schedule, optimal start function, one
1. The unit will not start regardless of the occupancy mode
when the UnitStatus= parameter indicates “Off Sw,” “Man
Ctrl,” “Off Alm,” “Off Net,” or “Off Man.” For a description of
these operating states, refer to “Operating State
Descriptions” on page 58.
McQuay OM-711-1
time event schedule, or an optional network schedule
indicates an occupied period.
Unocc
The Occupancy= parameter indicates “Unocc” when the unit
is in the unoccupied mode. In the unoccupied mode, the unit
is off and remains off unless unoccupied cooling (night set
up or purge) or unoccupied heating (night set back)
operation is activated. Refer to “Unoccupied Control” on
page 88. The unit is in the unoccupied mode if all of the
following conditions are true:
1. The Occ Mode= parameter is set to either “Unocc” or
“Auto” and any field supplied external time clock or a
tenant override switch contacts are open across
terminals 101 and 102 on the unit field terminal block
(TB2). For detailed information refer to “External Time
Clock or Tenant Override (Non-Timed)” in IM 710,
MicroTech II Vertical Self-Contained System Unit
Controller.
2. The Occ Mode= parameter is set to either “Unocc” or
“Auto” and the Bypass Time= parameter indicates 0
time.
3. The Occ Mode= parameter is not set to “Occ.”
4. The Occ Mode= parameter is set to “Auto” and the unit
internal time clock schedule, optimal start function, one
time event schedule, and optional network schedule all
indicate an unoccupied period.
Note: The unit reverts to unoccupied mode if the calibrate
function is active. For more information on calibrate
mode, refer to “Calibrate Mode” on page 51.
Tenant Override
The Occupancy= parameter indicates “TntOvrd” when the
unit is in the Tenant Override mode. In the Tenant Override
mode the unit starts up and function as it does in occupied
mode.1 The unit is in the Tenant Override mode if the
TntOvrd= parameter is set to a non-zero value. For details
regarding how the TntOvrd= is set, refer to “Tenant
Override” on page 43.
Occ Mode
Table 12: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Occupancy
Occ Mode= Auto
Parameter Name
Occupancy Mode
The unit can be set up for automatic or manual
occupied/unoccupied operation by setting the Occupancy
Mode. The following are descriptions of the four available
Occupancy Mode selections.
Auto
When the Occupancy Mode is set to “Auto,” the unit
operates automatically. This means that the Occupancy=
parameter changes automatically between “Occ” and
41
Unocc.” The Occupancy= parameter indicates “Occ” and
the unit starts if either the unit internal time clock schedule,
optimal start function, one time event schedule, or an
optional network schedule indicate an occupied period1. The
Occupancy= parameter indicates “Unocc” and the unit stops
if the unit internal time clock schedule, optimal start
function, one time event schedule, and an optional network
schedule all indicate an unoccupied period.
Exceptions:
1. The Occupancy= parameter is “Occ” and the unit starts
if a field supplied external time clock or a tenant
override switch signal in the form of a set of dry
contacts is closed across terminals 101 and 102 on the
unit field terminal block TB2 (binary input MCB-BI1
on)1. For detailed information refer to “External Time
Clock or Tenant Override (Non-Timed)” in IM 710,
MicroTech II Vertical Self-Contained Unit Controller.
2. The Occupancy= parameter indicates “Tenant
Override” and the unit starts if the Tenant Ovrd Time=
parameter is set to a non-zero value1.
3. The Occupancy= parameter indicates “Unocc” and the
unit stops if the Calibrate function is activated. Refer to
“Calibrate Mode” on page 51.
4. While the Occupancy= parameter indicates “Unocc,”
the unit can start and operate in the unoccupied heating
(night set back) or the unoccupied cooling (night set up
or purge) mode1. Refer to “Unoccupied Control” on
page 83.
Occ
When the Occupancy Mode is set to “Occ,” the Occupancy=
parameter indicates “Occ” and the unit starts and runs
continuously in the occupied mode1. Any scheduling
commands are prevented from shutting down the unit.
Exception:
The Occupancy= parameter indicates “Unocc” and the unit
stops if the Calibrate function is activated. Refer to
“Calibrate Mode” on page 51.
Unocc
When the Occupancy Mode is set to “Unocc,” the
Occupancy= parameter indicates “Unocc” and the unit is off
and remains off unless unoccupied cooling (night set up or
purge) or unoccupied heating (night set back) operation is
activated. Refer to “Unoccupied Control” on page 831.
Exceptions:
1. The Occupancy= parameter changes to “Occ” and the
unit starts if a field supplied external time clock or a
tenant override switch signal in the form of a set of dry
1. The unit will not start regardless of the occupancy mode
when the UnitStatus= parameter indicates “Off Sw,” “Man
Ctrl,” “Off Alm,” “Off Net,” or “Off Man.” For a description of
these operating states, refer to “Operating State
Descriptions” on page 58.
42
contacts is closed across terminals 101 and 102 on the
unit field terminal block TB2 (binary input MCB-BI1
on)1. For detailed information refer to “External Time
Clock or Tenant Override (Non-Timed)” in IM 710,
MicroTech II Vertical Self-Contained Unit Controller.
2. The Occupancy= parameter changes to “Tenant
Override” and the unit starts if the Tenant Ovrd Time=
parameter is set to a non-zero value1.
Tenant Override
When the Occupancy Mode is set to “Tenant Override,” the
Tenant Ovrd= parameter is set to the Tenant Ovrd= value.
The Occupancy= parameter indicates “Tenant Override” and
the unit starts and operates as in the occupied mode until the
Tenant Ovrd Time= parameter times out. Any scheduling
commands are prevented from shutting down the unit while
the tenant override operation is active.1
Note: Once the Occupancy Mode is set to “Tenant
Override” and the Tenant Ovrd= parameter is set to
the Tenant Ovrd= value, the Occupancy Mode
automatically reverts to the “Auto” setting.
Exception:
The Occupancy= parameter indicates “Unocc” and the unit
stops if the Calibrate function is activated. Refer to
“Calibrate Mode” on page 52.
Occ Src
Occ Src= is a status item that indicates the input source or
function that is responsible for setting the Occupancy=
parameter to “Occ.” There are a number of things that can
change the Occupancy= parameter to “Occ” and the Occ
Src= parameter is very helpful in determining which
function has started the unit.
None
The Occ Src= parameter indicates “None” when the
Occupancy= parameter indicates “Unocc” or “Tenant
Override.”
Int Sched
The Occ Src= parameter indicates “Int Sched” when the
Occupancy= parameter indicates “Occ” due to the unit
internal schedule or one event schedule indicating an
occupied period. Refer to “Scheduling” on page 44.
Net Sched
The Occ Src= parameter indicates “Net Sched” when the
Occupancy= parameter indicates “Occ” due to a network
schedule indicating an occupied period.
Occ Mode
The Occ Src= parameter indicates “Occ Mode” when the
Occupancy= parameter indicates “Occ” due to the
Occupancy Mode being manually set to “Occ.”
McQuay OM-711-1
Remote Sw
The Occ Src= parameter indicates “Remote Sw” when the
Occupancy= parameter indicates “Occ” due to a field
supplied external time clock or a tenant override switch
signal in the form of a set of dry contacts is closed across
terminals 101 and 102 on the unit field terminal block TB2
(binary input MCB-BI1 on). For detailed information refer
to “External Time Clock or Tenant Override (Non-Timed)”
in IM 710, MicroTech II Vertical Self-Contained Unit
Controller.
Table 13: Programmable parameters
Menu Name
Occupancy
Timer Settings
Item Name
Parameter Name
Occ Mode= Auto
Occupancy Mode
TntOvrd= 0 min
Tenant Override Timer
TntOvrd= 120 min
Tenant OverrideTime
Increment
There are two types of tenant override functions: timed and
non-timed. Timed override uses the Tenant Override Timer
and Tenant Override Time Increment to place the unit into
Tenant Override mode. Non-timed override uses a simple
field supplied SPST switch to override unoccupied
operation.
Timed Tenant Override
The tenant override button provided with the optional zone
temperature sensor packages is used to override unoccupied
operation for a preprogrammed time period. This time period
is set with the Tenant Override Time Increment. This value
can be adjusted from 0 to 300 minutes (default is 120
minutes).
When an occupant presses and releases the tenant override
button on the zone temperature sensor (ZNT1), the Tenant
Override Timer is set equal to the Tenant Override Time
Increment. (The button must be held for at least 1 second but
not more than 30 seconds.) The unit then starts and runs in
the Tenant Override mode, which is the same as occupied
mode except that it is temporary.1 The Tenant Override
Timer begins timing out and the unit runs until the timer
expires. If the tenant override button is pressed again while
the unit is operating in Tenant Override mode, the Tenant
Override Timer is reset to the Tenant Override Time
Increment and the unit continues to operate. For example,
assume that the Tenant Override Time Increment is 120
minutes. One press of the override button provides at 120
minutes of unit operation. If the button is pressed again 60
1. The unit will not start regardless of the occupancy mode
when the UnitStatus= parameter indicates “Off Sw,” “Man
Ctrl,” “Off Alm,” “Off Net,” or “Off Man.” For a description of
these operating states, refer to “Operating State
Descriptions” on page 58.
McQuay OM-711-1
Note: The same operation occurs if, instead of pressing the
override button on a zone temperature sensor, the
Occupancy Mode is set to “Tenant Override.” Once
set to “Tenant Override,” the Occupancy Mode
automatically reverts to the “Auto” setting once the
Tenant Override Timer is set to the Tenant Override
Time Increment.
Non-Timed Tenant Override
Tenant Override
Keypad/Display ID
minutes later, the Tenant Override Timer is reset to 120
minutes, and a total of 180 minutes of uninterrupted
operation results.
If an field supplied external time clock or a tenant override
switch signal in the form of a set of dry contacts is closed
across terminals 101 and 102 on the unit field terminal block
TB2 (binary input MCB-BI1 on), the unit is placed into
occupied mode1. When this switch is open, the unit is
controlled by any active scheduling function (internal time
clock schedule, optimal start function, one time event
schedule, or an optional network schedule). If there is no
active scheduling function, the unit remains in the
unoccupied mode. For detailed information refer to
“External Time Clock or Tenant Override (Non-Timed)” in
IM 710, MicroTech II Vertical Self-Contained Unit
Controller.
Operator Override
The Tenant Override Timer can be manually set. When the
Tenant Override Timer is set to a non-zero value, the unit
starts and runs in the Tenant Override mode regardless of
any scheduling features.1 The unit stops when the timer
expires. The Tenant Override Timer can be set from 0-300
minutes.
Note: If the Tenant Override Timer remaining time is larger
than the Tenant Override Time Increment, pressing
the tenant override button on the space sensor has no
effect. If the Tenant Override Timer remaining time
is less than the Tenant Override Time Increment,
pressing the tenant override button resets the Tenant
Override Timer to the Tenant Override Time
Increment value.
Emergency Override
Table 14: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Occupancy
Emerg Override=
Norm
Parameter Name
Emergency Override
Mode Flag
The unit can be shutdown by setting the Emergency
Override Mode Flag. When the Emergency Override Mode
Flag is set to “Off,” the UnitStatus= parameter indicates
“Off Net” and the unit remains off regardless of any time
schedule or other occupied or unoccupied start commands.
The only way a unit can be restarted is to set Emergency
43
Override Mode Flag back to “Norm.” The Emergency
Override Mode Flag can either be set manually at the unit
keypad or via a network signal.
Internal Daily Scheduling
Table 16: Programmable parameters
Keypad/Display ID
Scheduling
Menu Name
Item Name
Mon= 00:00 - 00:00
The unit can be scheduled for operation by using the
following three methods:
1) Unit internal time scheduling functions
Tue= 00:00 - 00:00
Tuesday Schedule
Wednesday Schedule
Thu= 00:00 - 00:00
Thursday Schedule
Fri= 00:00 - 00:00
Friday Schedule
Daily Schedule
3) Network time scheduling function
The next four sections: “Setting Controller Date and Time,”
“Internal Daily Scheduling,” “Holiday Scheduling,” and One
Event Scheduling” describe functions related to the internal
unit scheduling functions. These are followed by a section
describing the optimal start function, which can be used with
internal scheduling and network scheduling. This is followed
by two sections that describe the external time scheduling
and network time scheduling functions.
Setting Controller Date and Time
Sat= 00:00 - 00:00
Saturday Schedule
Sun= 00:00 - 00:00
Sunday Schedule
Hol= 00:00 - 00:00
Holiday Schedule
When the Occ Mode= parameter, described in “Auto/Manual
Operation” on page 40, is set to “Auto,” and the unit is not
disabled for other reasons, it starts and stops according to the
controller internal schedule. One start and one stop time can
be set for each day of the week and for designated holidays.
An example of how to use the keypad to enter or modify a
schedule is given in “Getting Started” on page 2.
As shown in Figure 5, each daily schedule has four
adjustable fields: Start Hour, Start Minute, Stop Hour, and
Stop Minute. The schedule shown would cause the unit to
start up at 6:30 a.m. and shut down at 6:00 p.m. every
Monday, Tuesday and Wednesday.
Figure 5: Daily schedule fields
Menu Line
Item Line Being Edited
**Edit Mode
Mon= 06:30 - 18:00
Tue= 06:30 - 18:00
Wed= 06:30 - 18:00
Table 15: Programmable parameters
Keypad/Display ID
Menu Name
Time/Date
Item Name
Current Time
Day= ddd
Current Day
Date= dd-mm-yyyy
Current Date
The MicroTech II controller uses the date and time to
execute its internal scheduling functions. Once set, the
battery backed internal time clock keeps the current time
regardless of whether or not power is being supplied to the
unit.
The time of day can be set by entering the hour (00-23),
minute (00-59), and second (00-59) into three fields of the
Current Time. Note that MicroTech II uses “military” time.
The day of the week is not adjustable. The Current Day is set
automatically by the controller based on the Current Date.
The current date can be set by entering the date (00-31),
month (01-12) and year (1999-2155) into the three fields of
the Current Date.
44
Stop Minute
Stop Hour
Start Minute
Start Hour
Parameter Name
Time= hh:mm:ss
Monday Schedule
Wed= 00:00 - 00:00
2) External time clock function
Provided the unit is not locally or remotely disabled, the unit
operates when any of these scheduling functions is calling
for occupied operation. Conversely, the unit enters the
unoccupied mode when all of these scheduling functions are
calling for unoccupied operation. Therefore, any unused
scheduling functions should be set for continuous
unoccupied operation. Refer also to “Auto/Manual
Operation” on page 40.
Parameter Name
For continuous unit operation, the schedule fields can be set
to “00:00-23:59.” For no unit operation for the entire day, the
schedule fields can be set to “00:00-00:00” (this is the
default setting).
Holiday Scheduling
Special operating hours can be scheduled for up to 16
holiday periods during the year by using the holiday
scheduling feature. (The wildcard character “*” in the above
table could be any number between 1 and 16.) Whenever a
holiday period occurs, the controller uses the Holiday
Schedule start and stop time for the period. For example,
assume that Christmas Eve occurs on a Thursday. The
building is shut down on both Christmas Eve and Christmas
Day, but operates normally on the weekend. This holiday
period would be scheduled by setting the Holiday Schedule
to “00:00-00:00” and setting the Holiday Period to “Dec 24 Dec 25.”
McQuay OM-711-1
Optimal Start
Table 17: Programmable parameters
Keypad/Display ID
Parameter Name
Menu Name
Item Name
Daily Schedule
Holiday= 00:00 - 00:00
Holiday Schedule
Holiday Schedule
Hol *= mmm dt - mmm dt
Holiday Period
If any of the 16 holiday periods are not required, the Holiday
Period is set to “N/A - N/A.”
One Event Scheduling
The unit can be scheduled to operate during a specified
period by using the one event scheduling feature. During the
specified period defined by the One Event Beginning
Date/Time and One Event Ending Date/Time parameters the
unit starts up and runs continuously regardless of any other
time scheduling functions. For example, assume that a space
served by the unit is occupied for a special event on March
12 from 5:00 p.m. to 10:00 p.m. when the normal time
scheduling has the unit shut off after 4:00 p.m. on that date.
This event can be accounted for by setting the One Event
Beginning Date/Time to “Mar 12 @ 17:00” and the One
Event Ending Date/Time to “Mar 12 @ 22:00.” If a oneevent schedule is not required, the One Event Beginning
Date/Time and One Event Ending Date/Time parameters are
both set to “N/A.”
The optimal start function can only be used with the unit
internal time schedule or a network supplied time schedule
that indicates “time-to-occupancy.” When the Optimal Start
Flag is set to “Yes,” the controller calculates an early start
time before each normally scheduled start. The controller
uses the start history, outdoor air temperature, and space
temperature to determine when the unit should start. The unit
may be started by the optimal start function up to four hours
before the scheduled start time.
If the Ctrl Temp= parameter, which is the temperature input
selected by the CtrlTemp Src= parameter, is below the
Effective Heating Enable Setpoint by more than half the
Heating Enable Deadband setting, optimal start operation is
based on the optimal start heating parameters. If the Ctrl
Temp= value is above the Effective Cooling Enable Setpoint
by more than half Cooling Enable Deadband setting, optimal
start operation is based on the optimal start cooling
parameters. Unit startup occurs at the scheduled start time if
the Ctrl Temp= value is in between these limits.
Table 19: Programmable parameter
Keypad/Display ID
Menu Name
Menu Name
Item Name
Parameter Name
Beg= mmm dd @ hh:mm
One Event Beginning
Date/Time
End= mmm dd @ hh:mm
One Event Ending
Date/Time
One Event
McQuay OM-711-1
Effective Cooling
Enable Setpoint
Clg Deadband= 1.0 ºF
Cooling Enable
Deadband
Eff Htg Spt= 75.0 ºF
Effective Heating
Enable Setpoint
Htg Deadband= 1.0 ºF
Heating Enable
Deadband
Optimal Start= No
Optimal Start Flag
Auto Update= Yes
Automatic Update
Flag
Zone Heating
Optimal Start
Parameter Name
Eff Clg Spt= 75.0 ºF
Zone Cooling
Table 18: Programmable parameters
Keypad/Display ID
Item Name
Htg Rate= 0.4 ºF/min
Heating Rate
Htg OAT= 35.0 ºF
Heating Outdoor Air
Temperature
Htg Zero OAT= 0 ºF
Heating Outdoor Air
Temperature Zero
Clg Rate= 0.4 ºF/min
Cooling Rate
Clg OAT= 85.0 ºF
Cooling Outdoor Air
Temperature
Clg Zero OAT= 100 ºF
Cooling Outdoor Air
Temperature Zero
45
When heating is required, a “heating rate” that varies with the outdoor air temperature is calculated using the formula:
Current OA Temperature – Heating Outdoor Air Temperature Zero
Calculated Heating Rate = Heating Rate × --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Heating Outdoor Air Temperature – Heating Outdoor Air Temperature Zero
The minutes before occupancy are calculated based on the following formula:
Effective Heating Enable Set Point-Current Space Temperature
Minutes Before Occupancy = -------------------------------------------------------------------------------------------------------------------------------------------------------Calculated Heating Rate
When cooling is required, a “cooling rate” that varies with the outdoor air temperature is calculated using the formula:
Current OA Temperature – Cooling Outdoor Air Temperature Zero
Calculated Cooling Rate = Cooling Rate × --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Cooling Outdoor Air Temperature – Cooling Outdoor Air Temperature Zero
The minutes before occupancy are calculated using the following formula:
Current Space Temperature – Effective Cooling Enable Set Point
Minutes Before Occupancy = -----------------------------------------------------------------------------------------------------------------------------------------------------------Calculated Cooling Rate
• If the Automatic Update Flag is set to “Yes,” the controller
revises the optimal start parameters after each start in
which
• they are used and the temperature change is significant.
External Time Scheduling
An external time clock can be used to schedule unit
operation. This is accomplished by a field supplied external
time clock signal in the form of a set of dry contacts wired
across terminals 101 and 102 on the unit field terminal block
TB2 (binary input MCB-BI1). In this case, all internal daily
schedules should be set to “00:00-00:00” (default setting).
For details on how to connect an external time clock, refer to
“Field Wiring” in IM 710, MicroTech II Vertical
Self-Contained Unit Controller.
Network Time Scheduling
A network time schedule can be used to operate the unit. In
this case, all internal daily schedules should be set to “00:0000:00” (default setting). Scheduling a unit via a network
signal is supported through optional communication
modules (BACnet/IP, BACnet MS/TP and LONMARK).
46
Alarm Monitoring
About Alarms
The MicroTech II Vertical Self-Contained Unit Controller is
programmed to monitor the unit for alarm conditions. Alarm
conditions are categorized in three types: “faults,”
“problems,” and “warnings.” In general, “faults” are more
serious than “problems” and “problems” more serious that
“warnings.” Therefore, “faults” are assigned a higher
priority than “problems” and “problems” a higher priority
than “warnings.” Within the three types, the alarms are
prioritized. Some alarms require manual clearing and some
are cleared automatically. Table 19 summarizes all alarms,
listing them by type and priority, and listing the required
clearing method.
If an alarm condition occurs, the controller displays a
message and executes the appropriate action to make the unit
fail-safe. The controller displays a local message on the unit
keypad/display and a remote indication on a Remote Alarm
Output (binary output MCB-BO4) wired to terminals for
field connection. For the meaning of each alarm, see “Alarm
Control” on page 84.
McQuay OM-711-1
Table 20: Unit alarms
Alarm Type
Fault
Problem
Alarm Message
Indication
Alarm Reset
Freeze
Smoke
MAT Sensor
OAT Sensor
Space Sensor
Return Sensor
Disch Sensor
Duct Hi Limit
Hi Return Tmp
Hi Disch Tmp
Lo Disch Tmp
Fan Fail
OA Dmpr Stuck
Freeze
MAT Sensor
EWT Sensor
OAT Sensor
Space Sensor
Return Sensor
Low Airflow
Heat Fail
Fan Retry
Hi Pres Ckt 1
Hi Pres Ckt 2
Hi Pres Ckt 3
Hi Pres Ckt 4
Hi Pres Ckt 5
Hi Pres Ckt 6
Circ 1 Lo P/Frost
Circ 2 Lo P/Frost
Circ 3 Lo P/Frost
Circ 4 Lo P/Frost
Circ 5 Lo P/Frost
Circ 6 Lo P/Frost
No Water Flow
Comp 1 Mp Alm
Comp 2 Mp Alm
Comp 3 Mp Alm
Comp 4 Mp Alm
Comp 5 Mp Alm
Comp 6 Mp Alm
CompB1 Clg Ena
CompB2 Clg Ena
CompB1 Comm Fail
CompB2 Comm Fail
Freezestat condition while SAF on
Smoke detected by smoke detector
MAT sensor failure while selected as CtrlTemp Src=MAT
OAT sensor failure while selected as Cntl Temp Src=OAT
Space temp sensor failure when CtrlTemp Src= parameter is set to “Space”
RAT sensor failure while selected as CtrlTemp Src=RAT
DAT sensor failure
Excessive discharge compartment pressure sensed by DHL sensor
RAT exceeded the Hi Return Tmp setting
DAT exceeded the Hi Disch Tmp setting
DAT fell below the Lo Disch Tmp setting
Airflow not sensed by PC7 after SAF was started
OA Dampers < 50% open after Startup (100% OA units only)
Freezestat tripped while SAF was off
MAT sensor failure when CtrlTemp Src= parameter not set to “MAT”
EWT sensor failure
OAT sensor failure when CtrlTemp Src= parameter not set to “OAT”
Space temp sensor failure on unit with RAT sensor
RAT sensor failure CtrlTemp Src= parameter not set to “Return”
DAT–MAT > 60 °F or DAT > 145 °F
Electric furnace safety lockout condition occurred
Airflow not sensed by PC7 after SAF was started
HP1 open indicating circuit #1 high refrigerant pressure
HP2 open indicating circuit #2 high refrigerant pressure
HP3 open indicating circuit #3 high refrigerant pressure
HP4 open indicating circuit #4 high refrigerant pressure
HP5 open indicating circuit #5 high refrigerant pressure
HP6 open indicating circuit #6 high refrigerant pressure
LP1 or FP1 open indicating circuit #1 low refrigerant pressure or frost condition
LP2 or FP2 open indicating circuit #2 low refrigerant pressure or frost condition
LP3 or FP3 open indicating circuit #3 low refrigerant pressure or frost condition
LP4 or FP4 open indicating circuit #4 low refrigerant pressure or frost condition
LP5 or FP5 open indicating circuit #5 low refrigerant pressure or frost condition
LP6 or FP6 open indicating circuit #6 low refrigerant pressure or frost condition
WF1 open indicating no water flow
Compressor #1 off due to motor protector (MP1)
Compressor #2 off due to motor protector (MP2)
Compressor #3 off due to motor protector (MP3)
Compressor #4 off due to motor protector (MP4)
Compressor #5 off due to motor protector (MP5)
Compressor #6 off due to motor protector (MP6)
Clg enable input to CCB1 off when cooling was on
Clg enable input to CCB2 off when cooling was on
Comm failure occurred between MCB and CCB1
Comm failure occurred between MCB and CCB1
Econo Position is > 10% after unit has been off for more than three minutes or
Econo Position is < 95% after unit has been in Mechanical Cooling with conditions
acceptable for Economizer Operation for more than three minutes.
PC7 sensed airflow when unit was off
Pressure drop across filter section exceeded the setting of PC5
Clg enable input to CCB1 on when cooling off
Clg enable input to CCB2 on when cooling off
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Manual
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Manual
Automatic
Automatic
Manual
Manual
Manual
Manual
Manual
Manual
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Automatic
Manual
Manual
Automatic
Automatic
Econo Stuck
Warning
McQuay OM-711-1
Airflow Switch
Dirty Filter
CompB1 H/W
CompB2 H/W
Manual
Manual
Manual
Manual
Manual
47
Remote Alarm Indication
The MicroTech II control system includes a Remote Alarm
Output (MCB-B04) to provide remote indication of alarm
conditions. Under normal (no active alarm) conditions, the
Remote Alarm Output (MCB-B04) is closed. The LED
associated with the alarm output indicates the state of the
output: On indicates MCB-B04 is closed, and off indicates
MCB-B04 is open. The Remote Alarm Output can be
connected to a field-supplied annunciator. If an alarm occurs,
the Remote Alarm Output condition changes to either an
“off” or “blinking” state. Each possible alarm condition can
be set up to cause the output to either blink rapidly, blink
slowly, turn off or remain on (no remote indication of the
alarm). Refer to “Configuring Remote Alarm Output” on
page 51.
Note: If there are multiple active alarms, only the highest
priority alarm affects this output. This is always the
alarm indicated by the Active Alarm 1 menu. Refer
to “Remote Alarm Output” in the “Field Wiring”
section of IM 710, MicroTech II Vertical SelfContained Unit Controller.
Local Alarm Indication (Keypad/Display)
Alarm information is provided via the unit keypad/display
by four “active” and eight “previous” alarm menus.
Up to four active alarms are displayed in the Active Alarm 1,
Active Alarm 2, Active Alarm 3, and Active Alarm 4 menus.
The highest priority active alarm is displayed in the Active
Alarm 1 menu, the second highest priority active alarm in
the Active Alarm 2, the third highest priority active alarm in
the Active Alarm 3 and the forth highest priority active
alarm in the Active Alarm 4 menu. If it happens that there
are more than four active alarms, the additional alarms do
not appear until one of these four active alarms are cleared.
When an active alarm is cleared the remaining active alarms
are resorted such that the highest priority active alarm
remaining is displayed in Active Alarm 1, the second highest
priority active alarm remaining is displayed in Active Alarm
2 and so forth. Figure 6 shows the typical display of an
active alarm menu. The first line of the display is the menu
line, the second line indicates the alarm name, the third line
indicates the alarm “type” (fault, problem, or warning) and
the forth line indicates the date and time the alarm occurred.
Whenever there is an active alarm, a red alarm LED on the
unit keypad turns on. If there are no active alarms, this LED
remains off.
When an active alarm is cleared, it is stored in the Previous
Alarm 1 menu. Any alarm that might be in the Previous
Alarm 1 menu is moved to the Previous Alarm 2 menu, any
alarm that might be in the Previous Alarm 2 menu is moved
to the Previous Alarm 3 menu and so forth. Any alarm that
might be in the Previous Alarm 8 menu is permanently
removed from the keypad. Figure 6 shows a typical display
of a previous alarm menu. The first line of the display is the
menu line, the second line indicates the alarm name, the third
line indicates the alarm “type” (fault, problem, or warning)
and the forth line indicates the date and time the alarm
occurred.
Figure 6: Active and previous alarm menu display
Menu Line
Alarm Name Item Line
Alarm Type Item Line
Alarm Date/Time Item Line
48
Active Alarm 1
Dirty Filter
Warning-Active
12-Mar-00 04:50:49
Previous Alarm 1
Dirty Filter
Warning-Clear
12-Mar-00 05:15:34
McQuay OM-711-1
Displaying Alarms
Active Alarms. When an active alarm exists the red LED on
the keypad is on. The active alarm or alarms can be viewed
as follows:
1. Pressing the Alarm key while the red LED
on the keypad is on changes the display to
the Active Alarm 1 menu.
2. Pressing the Right Arrow key changes the
display to the Active Alarm 2 menu.
Pressing the Right Arrow key again
changes the display to the Active Alarm 3
menu. Pressing the Right Arrow key again
changes the display to the Active Alarm 4
menu.
3. Pressing the Left Arrow key changes the
display back to the Active Alarm 3 menu.
Repeating this key two more times changes
the display back to the Active Alarm 1
menu.
Previous Alarm. When active alarms are cleared, they are
stored in the previous alarm menus. The previous alarm
menus can be viewed as follows:
1. Pressing the Back/Cancel key changes the
display to back to the main menu if not
already there.
2. Assuming the blinking cursor is positioned
on the System Summary menu, pressing the
Down Arrow (-) key six times changes the
cursor position to the Previous Alarms
menu.
3. Pressing the Enter/Save key changes the
display to the Previous Alarm 1 menu.
4. Pressing the Right Arrow key changes the
display to the Previous Alarm 2 menu.
Pressing the Right Arrow key again changes
the display to the Previous Alarm 3 menu.
Pressing the Right Arrow key five more
times changes the display to the Previous
Alarm 8 menu.
5. Pressing the Left Arrow key changes the
display back to the Active Alarm 7 menu.
Repeating this six more times changes the
display back to the Previous Alarm 1 menu.
McQuay OM-711-1
Clearing Alarms. Before any active alarm is cleared, the
alarm conditions that caused it must have returned to normal.
When the alarm conditions are no longer present, an active
alarm may be cleared either automatically or manually.
Note: Some of the devices that detect alarm condition
require a manual reset at the device before the alarm
can be cleared. Refer to Table 20 on page 47 for
listing of possible alarms and to determine whether
an alarm is manual or automatic reset.
An automatic reset active alarm immediately clears when the
alarm conditions that caused it disappear. A manual reset
active alarm is cleared using the keypad/display as follows.
1. The active alarm to be cleared is first
displayed. Refer to “Displaying Alarms”
on page 49.
2. Pressing the Clear Alarm key while the
active alarm to be cleared is in the display
sends a clear command to the controller.
This clears the active alarm and returns
the unit to normal operation if no other
alarms are active.
Remote Alarm Clearing
Although it is always recommended that active alarms be
cleared at the unit via the keypad/display, there are other
methods that effectively clear active alarms. Three such
methods are described in the following sections.
Unit System Switch (S1)
Cycling the main controller system switch (S1) located in the
unit main control panel has the effect of clearing the active
alarm menus. The disadvantage of clearing alarms in this
manor is that the active alarm data is not placed into the
previous alarm buffer and alarm information is lost.
Note: Turning off the unit power disconnect switch has the
same effect.
Manual Unit Enable/Disable Input
Disabling the unit via the manual unit enable/disable input
(this occurs when a field supplied and installed switch across
terminals 101 and 104 on the unit field terminal block (TB2)
is changed from the on (closed) to off (open) position. Refer
to the “Manual Unit Enable/Disable” section of IM 710,
MicroTech II Vertical Self-Contained Unit Controller.
Network Signal
The active alarms can be cleared via a network signal
through optional communication modules (including
BACnet/IP, BACnet MS/TP and LONMARK).
49
Table 21: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Freeze= Fast
Smoke= Fast
MAT Sensor= Fast
OAT Sensor= Fast
Space Sensor= Fast
Return Sensor= Fast
Disch Sensor= Fast
Alarm Out Faults
Duct Hi Limit= Fast
Hi Return Tmp= Fast
Hi Disch Tmp= Fast
Lo Disch Tmp= Fast
Fan Fail= Fast
OA Dmpr Stuck= Fast
Freeze= Slow
MAT Sensor= Slow
EWT Sensor= Slow
OAT Sensor= Slow
Space Sensor= Slow
Return Sensor= Slow
Heat Fail= Slow
Fan Retry= Slow
Hi Pres Ckt 1= Slow
Hi Pres Ckt 2 = Slow
Hi Pres Ckt 3 = Slow
Hi Pres Ckt 4 = Slow
Hi Pres Ckt 5 = Slow
Hi Pres Ckt 6 = Slow
Circ 1 Lo P/Frost = Slow
Circ 2 Lo P/Frost = Slow
Alarm Out Problems
Circ 3 Lo P/Frost = Slow
Circ 4 Lo P/Frost = Slow
Circ 5 Lo P/Frost = Slow
Circ 6 Lo P/Frost = Slow
No Water Flow = Slow
Water Reg Vlv = Slow
Comp 1 MP Alm = Slow
Comp 2 MP Alm = Slow
Comp 3 MP Alm = Slow
Comp 4 MP Alm = Slow
Comp 5 MP Alm = Slow
Comp 6 MP Alm = Slow
CompB1 Clg Ena = Slow
CompB2 Clg Ena = Slow
CompB1 Comm Fail = Slow
CompB2 Comm Fail = Slow
Econo Stuck = Off
Airflow Switch= Off
Alarm Out Warnings
Dirty Filter= Off
CompB1 H/W= Off
CompB2 H/W= Off
50
Parameter Name
Freeze Fault Remote Output Setup
Smoke Fault Remote Output Setup
MAT Sensor Fault Remote Output Setup
OAT Sensor Fault Remote Output Setup
Space Sensor Fault Remote Output Setup
Return Sensor Fault Remote Output Setup
Disch Sensor Fault Remote Output Setup
Duct Hi Limit Fault Remote Output Setup
Hi Return Tmp Fault Remote Output Setup
Hi Disch Tmp Fault Remote Output Setup
Lo Disch Tmp Fault Remote Output Setup
Fan Fail Fault Remote Output Setup
OA Dmpr Stuck Fault Remote Output Setup
Freeze Problem Remote Output Setup
MAT Sensor Problem Remote Output Setup
EWT Sensor Problem Remote Output Setup
OAT Sensor Problem Remote Output Setup
Space Sensor Problem Remote Output Setup
Return Sensor Problem Remote Output Setup
Heat Fail Problem Remote Output Setup
Fan Retry Problem Remote Output Setup
Circ 1 High P Problem Remote Output Setup
Circ 2 High P Problem Remote Output Setup
Circ 3 High P Problem Remote Output Setup
Circ 4 High P Problem Remote Output Setup
Circ 5 High P Problem Remote Output Setup
Circ 6 High P Problem Remote Output Setup
Circ 1 Lo P/Frost Problem Remote Output Setup
Circ 2 Lo P/Frost Problem Remote Output Setup
Circ 3 Lo P/Frost Problem Remote Output Setup
Circ 4 Lo P/Frost Problem Remote Output Setup
Circ 5 Lo P/Frost Problem Remote Output Setup
Circ 6 Lo P/Frost Problem Remote Output Setup
No Water Flow Problem Remote Output Setup
Water Reg Vlv Remote Output Setup
Comp 1 MP Alm Problem Remote Output Setup
Comp 2 MP Alm Problem Remote Output Setup
Comp 3 MP Alm Problem Remote Output Setup
Comp 4 MP Alm Problem Remote Output Setup
Comp 5 MP Alm Problem Remote Output Setup
Comp 6 MP Alm Problem Remote Output Setup
CompB1 Clg Ena Problem Remote Output Setup
CompB2 Clg Ena Problem Remote Output Setup
CompB1 Comm Fail Problem Remote Output Setup
CompB2 Comm Fail Problem Remote Output Setup
Econo Stuck Warning Remote Output Setup
Airflow Switch Warning Remote Output Setup
Dirty Filter Warning Remote Output Setup
CompB1 H/W Warning Remote Output Setup
CompB2 H/W Warning Remote Output Setup
McQuay OM-711-1
Configuring Remote Alarm Output
Each possible alarm condition can be configured to cause the
Remote Alarm Output (MCB-B04) to blink rapidly, blink
slowly, turn off, or remain on (no remote indication of the
alarm). This allows the action of the Remote Alarm Output
to be “tailored” according to the specific requirements of the
application. When there are no active alarms within the
controller the Remote Alarm Output is “on” continuously. If
an alarm output setup parameter is set to “Slow,” the Remote
Alarm Output cycles on and off at a slow rate when the
alarm occurs. If an alarm output setup parameter is set to
“Fast,” the Remote Alarm Output cycles on and off at a rapid
rate when the alarm occurs. If an alarm output setup
parameter is set to “Off,” the Remote Alarm Output turns off
when the alarm occurs. If an alarm output setup parameter is
set to “On,” the Remote Alarm Output remains on when the
alarm occurs.
For example, it may be necessary that only alarms that shut a
unit off completely (faults) be indicated remotely. In this
case all of the “fault” alarms are set to “Slow,” “Fast” or
“Off.” All others are set to “On.”
Refer to “Remote Alarm Output” in the “Field Wiring”
section of IM 710, MicroTech II Vertical Self-Contained Unit
Controller.
Setting Alarm Limits
Table 22: Programmable parameters
Keypad/Display ID
Menu Name
Alarm Limits
Item Name
Parameter Name
Hi Disch Alm= 170 ºF
High Discharge Air
Temperature Alarm
Limit
Lo Disch Alm= 40 ºF
Lo Discharge Air
Temperature Alarm
Limit
Hi Return Alm= 120 ºF
High Return Air
Temperature Alarm
Limit
Three of the alarm faults have adjustable limits that are used
to trigger the alarm. These are the Hi Disch Tmp, Lo Disch
Tmp and Hi Return Tmp faults. Although the default settings
should be suitable for most applications, the alarm limits can
be set as necessary via the unit keypad/display. The default
settings are shown in the table above.
Unit Configuration/Service
Parameters
Calibrate Mode
Table 23: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Unit Configuration
Calibrate Mode= No
Parameter Name
Calibrate Mode
Flag
Calibrate Mode is a special service mode used to calibrate
control actuator feedback signals and to zero static pressure
sensor inputs. When the Calibrate Mode Flag is set to “Yes,”
the position feedback potentiometers on the economizer air
damper, discharge fan inlet vane, waterside economizer
valve, modulating cooling valve and modulating heating
valve actuators are automatically calibrated. All the unit
static pressure transducers are also calibrated (or zeroed).
The following is a description of the Calibrate Mode
procedure.
When the Calibrate Mode Flag is set to “Yes,” the
Occupancy= parameter is overridden and is set to “Unocc”
and accordingly the unit shuts off. When the unit is off the
economizer air dampers, discharge vanes, waterside
economizer valve, modulating cooling valve, and
modulating heating valve actuators are driven to the 100%
open position for three minutes. After three minutes, the
controller records the analog input feedback values from the
actuators as equivalent to their fully open positions. The
controller then drives the actuators to the opposite or fully
“closed” position for three minutes. After three minutes, the
controller records the analog input feedback values from the
actuators as equivalent to their fully closed positions. The
controller also records the analog input voltage signals from
all connected static pressure transducers as equivalent to 0"
W.C.
Note: It is best to calibrate the unit with all the sensing
tubing to the static pressure sensors disconnected.
This assures that the sensors are truly seeing 0 “WC
when calibrated.
After the Calibrate Mode procedure is complete, the Ctrl
Mode= parameter is set to “Off,” which means the unit
remains off until the Ctrl Mode= parameter is set to
something other than “Off” as described in “Auto/Manual
Operation” on page 40.
Note: If the Calibrate Mode Flag is set to “Yes” while the
Manual Control= parameter in the Manual Control
menu is set to “Yes,” the Manual Control= parameter
reverts to “No.”
McQuay OM-711-1
51
Zone (Space) Temperature Sensor
Table 24: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Unit Configuration
Space Sensor= No
Parameter Name
Space Sensor
Present Flag
An optional zone (space) temperature sensor can be installed
in the field and wired to the unit. When the optional sensor is
installed, the Space Sensor Present Flag should be set to
“Yes.” When the optional sensor is not installed, the Space
Sensor Present Flag must be set to “No” to deactivate alarm
functions associated with an open circuit at the space
temperature analog input to the controller. The factory
setting for the Space Sensor Present Flag is “No.”
The optional space temperature sensor is required to take
advantage of the MicroTech II unoccupied heating (night
setback) and cooling (night setup and purge) functions.
These functions are disabled when the Space Sensor Present
Flag is set to “No.” Also, discharge air temperature setpoint
reset based on space temperature, optimal start and the
option of setting the CtrlTemp Src= parameter to “Space” are
not available when the Space Sensor Present Flag is set to
“No.”
Refer to “Zone Temperature Sensor Packages” in the “Field
Wiring” section of IM 710, MicroTech II Vertical SelfContained Unit Controller.
Miscellaneous Service Parameters
Menu Name
Unit
Configuration
Item Name
Parameter Name
MAT Sensor= Yes
MAT Sensor
Present Flag
OAT Sensor= No
OAT Sensor
Present Flag
Return Sensor= Yes
Return Sensor
Present Flag
2nd P Sensor= None
Second Pressure
Sensor Present
DF CapCtrl=
DuctPres
Discharge Fan
Capacity Control
Flush Econo= Yes
Waterside
Economizer Flush
Eng Units = English
Engineering
Control Flag
The Unit Configuration menu contains several
miscellaneous control parameters as listed in the table above.
These parameters are generally the type that are set at the
factory and might be adjusted when the equipment is started
up and generally do not required further adjustment. The
following sections describe these parameters.
MAT Sensor
52
OAT Sensor
This is an optional sensor. This sensor senses the
temperature of the outside air. The OAT sensor can be used
as the Crtl Temp Src= parameter if unit type is 100%
OA-DAC. When the Present Flag is set to “Yes.” Setting this
parameter to “No” disables the alarm function associated
with an open circuit at the OAT temperature sensor input. If
the Flag is set to “No” the sensor cannot be the control
temperature source.
RAT Sensor
All units are equipped with a return air temperature (RAT)
sensor. This sensor senses the temperature of the return air.
The RAT sensor is defaulted as the Crtl Temp Src=
parameter. Present Flag is set to “Yes.” Setting this
parameter to “No” disables the alarm function associated
with an open circuit at the RAT temperature sensor input. If
the Flag is set to “No” the sensor cannot be the control
temperature source.
2nd P Sensor
Table 25: Programmable parameters
Keypad/Display ID
All units are equipped with a mixed air temperature (MAT)
sensor. This sensor senses the temperature of the air entering
the cooling coils. If the unit is equipped with a waterside
economizer, the MAT sensor input is compared to the EWT
sensor input to determine if conditions are acceptable for
free cooling. The MAT sensor can be used as the Crtl Temp
Src= parameter if unit type is 100% OA-DAC. Present Flag
is set to “Yes.” Setting this parameter to “No” disables the
alarm function associated with an open circuit at the MAT
temperature sensor input. If the Flag is set to “No” the sensor
can not be the control temperature source.
The Second Pressure Sensor Present Flag is used to indicate
whether or not an optional static pressure sensor is installed
in the “second sensor” input location. When this parameter is
set to “Duct,” the controller assumes there is a second duct
static pressure sensor installed and displays and controls the
unit discharge inlet vanes or AFD based on the lower of the
two input values. When this parameter is set to “Bldg,” the
controller assumes there is a building static pressure sensor
installed in the “second sensor” location. In this case the unit
discharge inlet vanes or AFD are controlled to maintain the
building static pressure at a building pressure setpoint. When
this parameter is set to “None,” the controller assumes there
is not a second static pressure sensor installed and ignores
the associated analog input. For detailed information
regarding discharge and return fan capacity control, refer to
“Discharge Fan Capacity Control” on page 81.
DF CapCtrl
The Discharge Fan Capacity Control Flag used to select the
type of discharge fan capacity control to be used on a VAV
unit. If this parameter is set to “DuctPres,” the discharge fan
capacity is controlled to maintain the duct static pressure at
the duct static pressure setpoint. If this parameter is set to
“Position,” duct static pressure control is overridden and the
discharge fan capacity is controlled to the Remote Discharge
McQuay OM-711-1
Fan Capacity Setpoint. For detailed information regarding
discharge fan capacity control, refer to “Discharge Fan
Capacity Control” on page 81.
Control Timer Settings
Table 26: Programmable parameters
Flush Econo
All units with a waterside economizer have this option. The
Flag is set to “Yes.” Setting this parameter to “No” disables
the economizer flush option. The waterside economizer
valve will be opened and then closed during the unit’s
Startup Initialization.
Keypad/Display ID
Menu Name
Item Name
Service= 0 min
Fast Service Timer
Recirculate= 3 min
Recirculate State
Timer
Low DAT= 3 min
Low Discharge
Temperature Ignore
Timer
Max MWU= 90 min
Maximum Morning
Warm-up Timer
Tnt Ovrd= 120 min
Tenant override
Increment Timer
Start Init= 180 min
Startup Initialization
Timer
Bypass Valve Control
The bypass valve to the condenser is closed in all states
except the Fan Only, Mechanical Cooling, and Economizer.
The bypass valve is opened in the Fan Only State when
cooling is required so that water flow and an accurate
entering water temperature can be determined. The bypass
valve is open in the Mechanical Cooling State when
mechanical cooling is required and water is not flowing
through the waterside economizer. The bypass valve is open
in the Economizer State if an airside economizer is installed,
the position of the economizer exceeds 90% and the
Discharge Air Temperature is greater than the Effective
Cooling Setpoint plus DAT Clg Deadband / 2. The bypass
valve may be linked (or slaved) to the economizer valve so
that the bypass valve closes as the waterside economizer
valve opens. This provides nearly constant flow through the
unit regardless of the requirements of the economizer.
Timer
Settings
Eng Units
The Engineering Units Control Flag is used to select the
system of engineering units used for displaying data on the
keypad. If this parameter is set to “English,” the keypad data
is displayed in inch-pound (I-P) units. If this parameter is set
to “SI Canada,” the keypad data is displayed in the
International System of Units (SI) used in Canada. If this
parameter is set to “SI Europe,” the keypad data is displayed
in the International System of Units (SI) used in Europe.
Parameter Name
Post Heat= 0 min
Post Heat Timer
Bypass Valve= 300 sec
Compressor start
delay timer to allow
condenser valve to
open
Airflow= 60 sec
Airflow Switch Ignore
Timer
LP Alarm Delay= 45 sec
Low Pressure Switch
Ignore Timer
Comp Delay= 30 sec
Compressor start
delay timer with WRV
control
Several MicroTech II internal control timers can be adjusted
via the keypad/display Timer Settings menu. The following
sections describe these timers.
Service
Many of the internal control timers can be temporarily sped
up by using the Fast Service Timer. When set to a time value,
the Fast Service Timer begins counting down. While this
parameter is counting down the following normal unit timers
are set to 20 seconds:
• Startup Initialization Timer
• Recirc Timer
• Bypass Valve Timer
• Post Heat Timer
• Cooling Interstage Timer
• Heating Interstage Timer
These timers return to their normal settings if the Fast Service
Timer is manually set to 0 or when it counts down to 0.
Caution: The fast timers feature must be used only by a
knowledgeable service technician to facilitate
testing the unit.
Recirculate
The Recirculate State Timer defines the duration of the
Recirc operating state applicable on units with return air
(100% OA units have no Recirc operating state). Whenever
McQuay OM-711-1
53
a unit with return air is started or restarted, it always
transitions through a “start sequence,” which includes the
Startup, followed by the Recirc operating state. During the
Recirc operating state, the unit fans run while the outdoor air
dampers remain closed. Heating and cooling operation are
disabled during the Recirc operating state to allow the
“system” air temperature conditions to equalize before
temperature control begins. Once in the Recirc operating
state, the unit remains there until the Recirculate State Timer
expires.
Low DAT
The Low Discharge Temperature Ignore Timer sets the
duration of a time period after unit start up during which the
Lo Disch Tmp fault is ignored. This may be particularly
important in colder climates when a unit has been off for a
significant time period during which the unit, including the
discharge air temperature sensor, has become very cold. This
time period allows the unit to run long enough to warm the
discharge sensor above the alarm limit, preventing nuisance
unit alarm shutdown. For detailed information regarding the
Lo Disch Tmp fault refer to “Alarm Control” on page 84.
Max MWU
The Maximum Morning Warm-up Timer sets a maximum
duration for the MWU operating state applicable on units
with return air (100% OA units have no MWU operating
state). Whenever a unit with return air leaves the Recirc
operating state, it enters the MWU operating state if the Ctrl
Temp= parameter value is cold. The unit remains in the
MWU operating state until either the Ctrl Temp= parameter
value warms up or until the Maximum Morning Warm-up
Timer expires. For detailed information regarding MWU
operation, refer to “Heating: Multistage” on page 73, or
“Heating: Modulating Temperature Control” on page 74, as
applicable.
Tenant Override
The Tenant Override Time Increment sets the time period for
which the unit operates each time the tenant override button
on the optional space temperature sensor is pressed or the
Occ Mode= parameter is set to “Tenant Override.” The
Tenant Ovrd= parameter in the Occupancy menu is set or
reset to this value when the tenant override button is pressed
or the Occ Mode= parameter is set to “Tenant Override.”
The unit then operates until the Tenant Ovrd= parameter
counts down to 0. For detailed information regarding bypass
operation, refer to “Tenant Override” on page 43.
100% outdoor air hoods, the outdoor air dampers are driven
fully open. Discharge and return fan inlet vane actuators (if
present) are driven to a 17% minimum startup position.
Refer to “Operating States and Sequences” on page 57.
Post Heat
The Post Heat Timer sets the duration of the “post heat”
function available on VAV units. When a VAV unit changes
from heating to cooling operation, it may be necessary to
drive the unit airflow to a minimum position before allowing
the VAV boxes to change to their cooling mode of operation.
In some cases if this is not done, nuisance Duct Hi Limit
fault shutdown may result. This can be accomplished by
setting Post Heat Timer to a non-zero value in conjunction
with utilizing the VAV Box Output signal (MCB-BO12). For
detailed information regarding “post heat” operation, refer to
“Discharge Fan Capacity Control” on page 81. For detailed
information regarding the VAV Box Output, refer to “VAV
Box Output” in the “Field Wiring” section of IM 710,
MicroTech II Vertical Self-Contained Unit Controller.
Bypass Valve
When the Bypass Valve is opened during Fan Only, and the
adjustable Bypass Valve Timer (Bypass Valve= 300 sec) is
set, the unit remains in the Fan Only until the Bypass Valve
Timer expires so that water flow and entering water
temperature can be checked before the unit enters a cooling
state. The Waterside Economizer and Mechanical Cooling
operation are disabled until the Bypass Timer expires.
Airflow
The adjustable Airflow Timer (Airflow= 60sec) starts timing
down after Start-up Initialization and is not reset. The
Airflow Timer ignores the Fan Fail Alarm to allow the fan to
come up to speed. For detailed information regarding the
Fan Fail fault refer to “Alarm Control” on page 84.
LP Alarm Delay
When a compressor starts, the LP Alarm Delay timer
(45 sec) delays the low pressure alarm until the timer has
timed out.
Compressor Delay
The Compressor Delay Timer is used with Head Pressure
Control. The unit does not enter mechanical cooling until the
compressor delay timer has timed out to allow water to begin
flowing through the condenser.
Start Init
The Startup Initialization Timer defines the duration of the
Startup operating state. When a unit is started or restarted, it
always transitions through a “start sequence” that begins
with the Startup operating state. During the Startup operating
state, the unit fans remain off and heating and cooling are
disabled. On units equipped with return air, the outdoor air
damper actuator is driven closed. On units equipped with
54
McQuay OM-711-1
Manual Output Control
Table 27: Programmable parameters
Keypad/Display ID
Menu Name
Manual Control
Item Name
Parameter Name
Manual Control = No
Manual Control Mode
Flag
Discharge Fan = Off
Manual Discharge
Fan Control Flag
Fan Operation = Off
Manual Fan
Operation Output
Control Flag
Alarm = Normal
Manual Remote
Alarm Output Control
Flag
Economizer = Auto
Manual Economizer
Output Control Flag
Bypass Valve = Auto
Manual Bypass Valve
Output Control Flag
Water Reg Vlv = Auto
Manual Regulating
Valve Output Control
Flag
OA Damper = Close
Manual OA Damper
Control Flag
Mod Cooling = Auto
Manual Modulating
Cooling Valve Control
Flag
Mod Heating = Auto
Manual Modulating
Heating Valve Control
Flag
VAV Output = Heat
Manual VAV Box
Output Control Flag
Disch Vanes = Auto
Manual Discharge
Vane Actuator
Control Flag
Disch VFD = Auto
Manual Discharge
AFD Control Flag
The Manual Control menu is a special service menu that can
be used to control many of the outputs on the main control
board (MCB) in a manual mode. This can be used to test the
operation of the various devices controlled by the outputs.
This is very useful in determining whether a problem is the
result of a wiring problem or defective device rather than a
problem within the main controller.
the unit remains off until the Ctrl Mode= parameter is
changed to something other than “Off.” Refer to
“Auto/Manual Operation” on page 40.
Note: If the Calibrate Mode= parameter in the Unit
Configuration menu is set to “Yes” while the Manual
Control Mode Flag is set to “Yes,” the Manual
Control Mode Flag reverts to “No.”
Discharge Fan
The Manual Discharge Fan Control Flag is used to manually
turn the discharge air fan on and off. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“On” the discharge air fan is turned on. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“Off” the discharge air fan is turned off.
Fan Operation
The Manual Fan Operation Output Control Flag is used to
manually turn the Fan Operation Output (MCB-BO3) on and
off. When the Manual Control Mode Flag is set to “Yes” and
this parameter is set to “On” the Fan Operation Output is
turned on. When the Manual Control Mode Flag is set to
“Yes” and this parameter is set to “Off” the Fan Operation
Output is turned off. For detailed information regarding the
Fan Operation Output, refer to “Fan Operation Output” in
the “Field Wiring” section of IM 710, MicroTech II Vertical
Self-Contained Unit Controller.
Alarm
The Manual Remote Alarm Output Control Flag is used to
manually turn the Remote Alarm Output (MCB-BO4) on
and off. When the Manual Control Mode Flag is set to “Yes”
and this parameter is set to “Normal” the Remote Alarm
Output is turned on. When the Manual Control Mode Flag is
set to “Yes” and this parameter is set to “Alarm” the Remote
Alarm Output is turned off. For detailed information
regarding the Remote Alarm Output, refer to “Remote
Alarm Output” in the “Field Wiring” section of IM 710,
MicroTech II Vertical Self-Contained Unit Controller.
Manual Control
Economizer (Waterside Economizer)
The Manual Control Mode Flag is used to turn the manual
control mode of operation on and off. When this parameter is
set to “No” the unit operates normally. When this parameter
is set to “Yes” normal operation of the control outputs is
overridden and the condition of each output is defined by
setting the remaining items within the Manual Control menu.
All alarms are inactive when the Manual Control Mode Flag
is set to “Yes” except the Duct Hi Limit fault. If the Duct Hi
Limit fault occurs while the Manual Control Mode Flag is
set to “Yes,” the unit is shut off on the fault, the Manual
Control Mode Flag reverts to “No,” and the Ctrl Mode=
parameter in the System menu reverts to “Off.” This means
The Economizer Control Mode Flag is used to manually
drive the economizer actuator open and closed. When the
Manual Control Mode Flag is set to “Yes” and this parameter
is set to “Open” the open economizer actuator output (MCBB06) is turned on and the actuator strokes open continuously.
When the Manual Control Mode Flag is set to “Yes” and this
parameter is set to “Close” the close economizer actuator
output (MCB-B05) is turned on and the actuator strokes
closed continuously. When the Manual Control Mode Flag is
set to “Yes” and this parameter is set to “Auto” the open and
closed economizer actuator outputs remain off and the
actuator remains at it current position.
McQuay OM-711-1
55
Bypass Valve
The Bypass Valve Control Mode Flag is used to manually
drive the bypass valve open and closed. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“Open” the open bypass valve output (MCB-B08) is turned
on and the actuator strokes open continuously. When the
Manual Control Mode Flag is set to “Yes” and this parameter
is set to “Close” the close bypass valve output (MCB-B07) is
turned on and the actuator strokes closed continuously.
When the Manual Control Mode Flag is set to “Yes” and this
parameter is set to “Auto” the open and closed bypass valve
outputs remain off and the actuator remains at it current
position.
Water Regulating Valve
The Water Regulating Valve Control Mode Flag is used to
manually drive the water regulating valve open and closed.
When the Manual Control Mode Flag is set to “Yes” and this
parameter is set to “Open” the open water regulating valve
output (MCB-B08) is turned on and the actuator strokes
open continuously. When the Manual Control Mode Flag is
set to “Yes” and this parameter is set to “Close” the close
water regulating valve output (MCB-B07) is turned on and
the actuator strokes closed continuously. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“Auto” the open and closed water regulating valve outputs
remain off and the actuator remains at it current position.
OA Damper (Airside Economizer)
The Manual OA Damper Control Flag is used to manually
drive the outdoor air dampers open and closed. When the
Manual Control Mode Flag is set to “Yes” and this parameter
is set to “Open” the open outdoor damper output (MCBBO2) is turned on and the outdoor air dampers stroke open
continuously. When the Manual Control Mode Flag is set to
“Yes” and this parameter is set to “Close” the close outdoor
damper output (MCB-BO2) is turned off and the outdoor air
dampers stroke closed continuously.
Mod Cooling
The Manual Modulating Cooling Valve Control Flag is used
to manually drive the modulating cooling valve open and
closed. When the Manual Control Mode Flag is set to “Yes”
and this parameter is set to “Open” the open cooling valve
output (MCB-BO8) is turned on and the cooling valve
strokes open continuously. When the Manual Control Mode
Flag is set to “Yes” and this parameter is set to “Close” the
close cooling valve output (MCB-BO7) is turned on and the
cooling valve strokes closed continuously. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“Auto” the open and close cooling valve outputs remain off
and the cooling valve remains at its current position.
Mod Heating
The Manual Modulating Heating Valve Control Flag is used
to manually drive the modulating heating valve open and
closed. When the Manual Control Mode Flag is set to “Yes”
56
and this parameter is set to “Open” the open heating valve
output (MCB-BO10) is turned on and the heating valve
strokes open continuously. When the Manual Control Mode
Flag is set to “Yes” and this parameter is set to “Close” the
close heating valve output (MCB-BO9) is turned on and the
heating valve strokes closed continuously. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“Auto” the open and close heating valve outputs remain off
and the heating valve remains at its current position.
VAV Output
The Manual VAV Box Output Control Flag is an adjustable
item used to manually turn the VAV Box Output (MCBBO12) on and off. When the Manual Control Mode Flag is
set to “Yes” and this parameter is set to “Cool” the VAV Box
Output is turned on. When the Manual Control Mode Flag is
set to “Yes” and this parameter is set to “Heat” the VAV Box
Output is turned off. For detailed information regarding the
VAV Box Output, refer to “VAV Box Output” in the “Field
Wiring” section of IM 710, MicroTech II Vertical SelfContained Unit Controller.
Disch Vanes
The Manual Discharge Vane Actuator Control Flag is used to
manually drive the discharge fan inlet vanes open and
closed. When the Manual Control Mode Flag is set to “Yes”
and this parameter is set to “Open” the open discharge inlet
vanes output (MCB-BO14) is turned on and the vanes stroke
open continuously. When the Manual Control Mode Flag is
set to “Yes” and this parameter is set to “Close” the close
discharge inlet vanes output (MCB-BO13) is turned on and
the vanes stroke closed continuously. When the Manual
Control Mode Flag is set to “Yes” and this parameter is set to
“Auto” the open and close discharge inlet vanes outputs
remain off and the vanes remain at their current position.
Disch VFD
The Manual Discharge VFD Control Flag is used to
manually increase and decrease the discharge air fan AFD
speed. When the Manual Control Mode Flag is set to “Yes”
and this parameter is set to “Faster” the increase discharge
fan AFD speed output (MCB-BO14) is turned on and the
AFD speed increases continuously. When Manual Control
Mode Flag is set to “Yes” and this parameter is set to
“Slower” the decrease discharge fan AFD speed output
(MCB-BO13) is turned on and the AFD speed decreases
continuously. When the Manual Control Mode Flag is set to
“Yes” and this parameter is set to “Auto” the increase and
decrease discharge fan AFD speed outputs remain off and
the AFD remains at its current speed.
McQuay OM-711-1
Description of Operation
The following sections describe how the various discharge
air temperature control unit processes function to maintain
temperature, ventilation and pressure control. The
“Operating States and Sequences” section provides an
overall description of unit operation. The subsequent
sections provide detailed descriptions of the various control
processes and how the related setpoints and parameters
affect them. The related setpoints and parameters are listed at
the beginning of each applicable sub-section. The default
keypad programmable values are shown in italic letters.
Note: Not all the features covered in this section apply to
all units depending on the specific unit options. The
applicable items should be read and understood
before making setpoint or control parameter changes.
Operating States and Sequences
About Operating States
Operating states define the current overall status of the unit.
The operating state can be displayed and the unit operating
condition can be quickly determined by viewing the
UnitStatus= parameter in the System menu. Each operating
state summarizes the following information:
• Discharge fan status
• Outdoor air damper status
• Discharge airflow capacity
• Airside and Waterside Economizer status
• Heating system status
• Cooling system status
• Fan Operation Output status (MCB-BO3)
• VAV Box Output status (MCB-BO12)
• Pump Start Ouput status (CCB1-BO3)
Table 28 shows the all the normal operating states and the
status information they summarize.
Table 28: Operating states
Operating Discharge/
State
Fans
OA Dampers Discharge
Airside
Waterside
Mechanical
VAV Box
Pump
Heat
Fan Output
Output
Airflow
Economizer Economizer
Cooling
Output
Output
Enabled
(MCB-BO3)
Enabled
(MCB-BO12) (CCB1-BO3)
(MCB-BO2) Capacity
Airflow
Waterflow
Closed or
Off
Off
Closed
0%
Closed
Off
No
No
Opena
Startup
Off
Closed
0%
Closed
Off
No
No
Closed
Open
Offh
Recirc
On
Closed
Modulating
Closed
Off
No
No
Closed
Open
Off
Fan Only
On
Open
Modulatingc
Minimum
Off
No
No
Closed
Econo
On
Open
Modulating
Modulating
Modulating
No
No
Closed
Closed
On
Cooling
On
Opene
Modulating
Off or Openg
No
Yes
Closed
Closed
On
MWU
On
Closed
Modulating
Closed
Off
Yes
No
Closed
Open
Off
Heating
On
Open
Modulating
Minimum
Off
Yes
No
Closed
Open
Off
Modulating
or Opene
Openb
Closed or
Opend
Closed or
Off
Oni
Min DAT
On
Open
Modulatingc
Minimum
Off
No
No
Closed
UnocEcon
On
Closed
Modulating
Modulating
Modulating
No
No
Closed
Open
On
Off or Openg
No
Yes
Closed
Open
On
Off
Yes
No
Closed
Open
Off
UnocClg
On
Closed
Modulating
UnocHtg
On
Closed
Modulating
a.
b.
c.
d.
e.
f.
g.
h.
i.
Closed or
Openf
Closed
Opend
Off
If the DF CapCtrl= parameter in the Unit Configuration menu is set to “DuctPress,” the output turns off (open) 30 seconds after the unit airflow switch (PC7) opens. In this case if
PC7 is closed, the Fan Operation Output remains on (closed).
The VAV Box Output is normally in the closed (cool) position in this operating state unless airflow is detected. If airflow is detected, the VAV Box Output switches to the open
(heat) position
The discharge airflow is driven to minimum for an adjustable post heat time period the Post Heat= parameter is set to a non-zero value when the unit enters the Fan Only or Min
DAT operating state from either the Recirc or any heating operating state. Refer to “Post Heat” in the “Discharge Fan Airflow Control” section of this manual.
The VAV Box Output is normally in the closed (cool) position in this operating state. However, if the VAV Box Output is in the open (heat) position upon entering this operating
state, it remains in the open (heat) position for a time period defined by the Post Heat= parameter or unit the discharge inlet vane position drops below 17% (AFD speed below
25%).
When the OA Ambient= parameter indicates “Low,” the economizer outdoor air dampers is fully open; when the OA Ambient= parameter indicates “High,” the economizer outdoor air dampers are at Eff Min OA Pos= value.
When the OA Ambient= parameter indicates “Low,” the economizer outdoor air dampers is fully open; when the OA Ambient= parameter indicates “High,” the economizer outdoor air dampers are at Eff Min OA Pos= value.
Waterside Economizer will be off if the temperature delta between EWT and MAT is less than the differential.
When the Flush Mode is set to “Yes,” the Pump Output is on during startup initialization. Only available with waterside economizer control.
The Pump Output is on during the Fan Only State if cooling is required.
McQuay OM-711-1
57
Operating State Descriptions
The following sections describe each of the unit operating
states.
Off
There are five different Off operating states. In any of the
Off operating states the unit is shut down. The fans are off,
the outdoor air dampers are closed, any fan inlet vanes or
VFD are driven to 0%. Cooling and heating are disabled.
The Fan Operation Output (MCB-BO3) is open and the VAV
Box Output (MCB-BO12) is in the closed (cool) position
unless airflow is detected by the PC7 airflow switch, in
which case it in the open (heat) position.
The five different Off operating states are described in the
following sections:
Off Unoc. Generally, the unit operating state is Off Unoc
when it the unit is being scheduled on and off by a time clock
function and the time schedule indicates an unoccupied
period. Specifically, the operating state is Off Unoc when the
Occupancy= parameter indicates “Unocc” and none of the
unoccupied unit operation functions are active. For details
regarding the Occupancy= parameter refer to “Occupancy”
on page 41. For details regarding unoccupied unit operation
functions refer to “Unoccupied Control” on page 83
Off Net. The unit operating state is Off Net when the Appl
Mode= parameter is set to “Off” via a network signal and the
Ctrl Mode= parameter is set to “Auto.” For detailed
information regarding the Appl Mode= and Ctrl Mode=
parameter, refer to“Auto/Manual Operation” on page 40.
The unit operating state is also Off Net when the Emerg
Override= parameter in the Occupancy menu is set to “Off.”
Refer to “Emergency Override” on page 43.
Off Sw. The unit operating state is Off Sw when a field
supplied and installed switch across terminals 101 and 104
on the unit field terminal block (TB2) is in the on or closed
position (binary input MCB-BI2 on). Refer to “Manual Unit
Enable/Disable” in IM 710, MicroTech II Vertical
Self-Contained Unit Controller.
Off Alm. The unit operating state is Off Alm when an active
alarm of the “fault” type has a unit shut down. Refer to
“Alarm Monitoring” on page 46 for a description of “fault”
alarms.
Off Man. The unit operating state is Off Man when the Ctrl
Mode= parameter is set to “Off.” For detailed information
regarding the Ctrl Mode= parameter, refer to “Ctrl Mode” on
page 40.
Startup
When a unit is commanded to start the unit always enters the
Startup operating state from the Off operating state. The unit
remains in the Startup operating state for an adjustable time
period defined by the Start Init= parameter in the Timer
Settings menu (default value is 180 seconds) before entering
the Recirc operating state. During the Startup operating state
58
the unit is prepared for startup. The fans remain off, the
outdoor air dampers are driven closed, any fan inlet vanes
are driven to a fixed 17% minimum position (AFD remains
at 0% speed). Cooling and heating remain disabled. The Fan
Operation Output (MCB-BO3) is closed and the VAV Box
Output (MCB-BO12) is in the open (heat) position.
For more information regarding the Startup operating state,
refer to“Startup Control” on page 61.
Recirc
Units with return air always enter the Recirc operating state
after the completion of the Startup operating state. In the
Recirc operating state fans are started and operate while the
outdoor air dampers remain closed. This allows temperature
conditions throughout the unit and space to equalize before
temperature control begins. Cooling and heating remain
disabled. The Fan Operation Output (MCB-BO3) is closed,
the VAV Box Output (MCB-BO12) is in the open (heat)
position and in VAV applications normal duct static pressure
or position control is maintained. The Recirc operating state
is particularly important for applications in which the return
air temperature sensor is being used for heat/cool
changeover control. The unit remains in the Recirc operating
state until the Recirculate State Timer expires. This timer is
adjustable from 2 to 60 minutes with the Recirculate=
parameter in the Timer Settings menu.
Note: 100% outdoor air units do not transition through the
Recirc operating state.
For more information regarding the Recirc operating state,
refer to “Startup Control” on page 61.
Fan Only
The unit enters the Fan Only operating state during occupied
operation when cooling and heating are either not required
based unit heat/cool changeover function or are disabled.
During the Fan Only operating state, the outdoor air dampers
are either 100% open on a 100% outdoor air unit or are
controlled to the Eff Min OA Pos= parameter in the OA
Damper menu. Cooling and heating operation is disabled.
The Fan Operation Output (MCB-BO3) is closed, the VAV
Box Output (MCB-BO12) is normally in the close (cool)
position and in VAV applications normal duct static pressure
or position control is maintained.
Note: The VAV Box Output can be in the open (heat)
position during the Fan Only operating state when
“post heat” operation is active. For detailed
information regarding “post heat” operation, refer to
“Post Heat Operation” on page 83.
Econo
The unit enters the Econo operating state when cooling is
required during occupied operation and economizer
operation is enabled. During the Econo operating state,
mechanical cooling and heating are disabled. The
Economizer Valve or Air Damper are modulated to maintain
McQuay OM-711-1
the discharge air temperature at the Eff Clg Spt= parameter
in the Discharge Cooling menu. The Fan Operation Output
(MCB-BO3) is closed, the VAV Box Output (MCB-BO12) is
in the closed (cool) position and in VAV applications normal
duct static pressure or position control is maintained.
Note: 100% outdoor air units do not transition through the
Econo operating state.
For detailed information regarding economizer operation,
refer to “Economizer” on page 64.
Cooling
The unit enters the Cooling operating state during occupied
operation when cooling is required and the economizer is
either disabled, not present, or already fully opened. During
the Cooling operating state, the outdoor air dampers are fully
open if the unit is a 100% outdoor air unit or if Airside
economizer operation is enabled. The outdoor air dampers
are controlled to the Eff Min OA Pos= parameter if Airside
economizer operation is disabled or not present. If all
cooling is allowed the Waterside Economizer Valve will be
fully open. Mechanical cooling is supplied as required to
maintain the discharge air temperature at the Eff Clg Spt= in
the Discharge Cooling menu. The Fan Operation Output
(MCB-BO3) is closed, the VAV Box Output (MCB-BO12) is
in the closed (cool) position and in VAV applications normal
duct static pressure, Bldg Static pressure or position control
is maintained. Heating is disabled.
For detailed information regarding the cooling operation,
refer to“Cooling: Multistage” on page 67 or “Cooling:
Modulating” on page 72 as applicable.
MWU
When the unit transitions from unoccupied to occupied
operation and heating is required to warm the Ctrl Temp=
parameter up to the Eff Htg Spt= setting in the Zone Heating
menu, the unit enters the MWU (Morning Warm-up)
operating state after the Startup and Recirc operating states
are complete. The MWU operating state is similar to the
Heating operating state except that the outdoor air dampers
are held closed rather than controlled to the Eff Min OA
Pos= parameter. Once entering the MWU operating state,
the unit remains there until either the Ctrl Temp= parameter
warms up to the Eff Htg Spt= setting in the Zone Heating
menu or until a maximum morning warm-up time period
expires. This time period is defined by the Max MWU=
parameter in the Timer Settings menu. The Fan Operation
Output (MCB-BO3) is closed, the VAV Box Output (MCBBO12) is in the open (heat) position and in VAV applications
normal duct static pressure, Bldg Static pressure or position
control is maintained. Cooling is disabled.
Note: 100% outdoor air units do not transition through the
MWU operating state.
For detailed information regarding morning warm-up
heating operation, refer to “Heating: Multistage” on page 73,
McQuay OM-711-1
or “Heating: Modulating Temperature Control” on page 74,
as applicable.
Heating
The unit enters the Heating operating state when heating is
required during occupied operation. During the Heating
operating state, the outdoor air dampers are either 100%
open if the unit is a 100% outdoor air unit or controlled to
the Eff Min OA Pos= parameter. Cooling is disabled. The
Fan Operation Output (MCB-BO3) is closed, the VAV Box
Output (MCB-BO12) is in the open (heat) position and in
VAV applications normal duct static pressure, Bldg Static
pressure or position control is maintained.
For detailed information regarding heating operation, refer
to“Heating: Multistage” on page 73, or “Heating:
Modulating Temperature Control” on page 74 as applicable.
Min DAT
The unit enters the Min DAT operating state during occupied
operation when neither cooling nor heating is required based
on the unit heat/cool changeover function but the discharge
air temperature falls below the Eff Clg Spt= parameter in the
Discharge Cooling menu. The Min DAT operating state
prevents cold discharge air temperatures during what would
normally be the Fan Only operating state. During the Min
DAT operating state, the outdoor air dampers are either
100% open if the unit is a 100% outdoor air unit or are
controlled to the Eff Min OA Pos= parameter. Cooling is
disabled. The Fan Operation Output (MCB-BO3) is closed,
the VAV Box Output (MCB-BO12) is normally in the closed
(cool) position and in VAV applications normal duct static
pressure, Bldg Static pressure or position control is
maintained.
Note: The VAV Box Output can be in the open (heat)
position during the MinDAT operating state when
“post heat” operation is active. For detailed
information regarding “post heat” operation, refer to
“Post Heat Operation” on page 83.
Note: The Min DAT operating state is available on units
with modulating or multistage heating only.
For detailed information regarding the Min DAT operating
state, refer to “Discharge Air Low Limit Control” on page 74
(multistage heat) or “Discharge Air Low Limit Control” on
page 75 (modulating heat) as applicable.
UnocEcon
The unit enters the UnocEcon operating state if suitable for
free cooling when “purge” or unoccupied cooling (night
setup) operation is required. During the UnocEcon operating
state, the Economizer is modulated to maintain the discharge
air temperature at the Eff Clg Spt= parameter in the
Discharge Cooling menu. Mechanical cooling is disabled.
The Fan Operation Output (MCB-BO3) is closed, the VAV
Box Output (MCB-BO12) is in the open (heat) position to
allow VAV boxes to open fully and in VAV applications
59
normal duct static pressure or position control is maintained.
Heating is disabled.
Note: 100% outdoor air units do not transition through the
For detailed information regarding the unoccupied heating
operation, refer to “Unoccupied Heating (Night Setback)” on
page 86.
UnocFanO
UnocEcon operating state
For detailed information regarding unoccupied economizer
operation, refer to “Unoccupied Cooling (Night Setup)” on
page 83 and “Purge” on page 84.
UnocClg
The unit enters the UnocClg operating state when
unoccupied cooling (night setup) operation is required and
the economizer is either disabled, not present, or already
fully opened. During the UnocClg operating state, the
outdoor air dampers are fully open if the unit is a 100%
outdoor air unit or if Airside economizer operation is
enabled. The outdoor air dampers are at 0% if Airside
economizer operation is disabled or not present. If all
cooling is allowed the Waterside Economizer Valve will be
fully open. The Fan Operation Output (MCB-BO3) is closed,
the VAV Box Output (MCB-BO12) is in the open (heat)
position to allow VAV boxes to open fully and in VAV
applications normal duct static pressure, Bldg Static pressure
or position control is maintained. Heating is disabled.
For detailed information regarding the unoccupied cooling
operation, refer to “Unoccupied Cooling (Night Setup)” on
page 83.
UnocHtg
The unit enters the UnocHtg operating state when
unoccupied heating (night setback) operation is required.
During the UnocHtg operating state, the outdoor air dampers
are closed. The Fan Operation Output (MCB-BO3) is closed,
the VAV Box Output (MCB-BO12) is in the open (heat)
position to allow VAV boxes to open fully and in VAV
applications normal duct static pressure, Bldg Static pressure
or position control is maintained. Cooling is disabled.
The UnocFanO operating state is not a “typical” operating
state. If night set back operation is activated while the unit
heating is disabled or if the unit is not equipped with heating
equipment, the unit with enter the UnocFanO operating state
in lieu of the UnocHtg operating state. Unit operation is the
same as described for the Fan Only operating state except
that the outdoor air dampers are controlled as in the UnocHtg
operating state.
The unit will also enter the UnocFanO operating state if
cooling or heating are disabled while in the UnocEcon,
UnocClg or UnocHtg operating states. If entering the
UnocFanO operating state from the UnocEcon or UnocClg
operating state, the outdoor dampers are controlled as
described for the UnocClg operating state.
For detailed information regarding the unoccupied heating or
cooling operation, refer to “Unoccupied Control” on page 83.
Man Ctrl
The unit enters the Man Ctrl operating state when the
Manual Control= parameter in the Manual Control menu is
set to “Yes.” During manual operation, all the unit control
functions are disabled and the main control board (MCB)
outputs can be turned on and off manually by setting the
parameters contained in the Manual Control menu.
For detailed information regarding manual unit control, refer
to “Manual Output Control” on page 55.
Operating State Sequence Chart
Operating states and the transitions between them help to
describe the unit sequences of operation. Figure 7 shows all
of the operating state transitions that can occur as a result of
normal control. Depending on the unit options, some
operating states may not apply.
Figure 7: Operating state sequence chart
Any-State
OFF
Startup
Recirc
UnocClg
Cooling
MWU
Heating
UnocHtg
UnocEcono
Economizer
Fan Only
Min DAT
60
McQuay OM-711-1
Startup Control
boxes to open fully to facilitate efficient system air
circulation.
A self-contained unit can startup and run for a variety of
reasons. Examples are the internal time schedule function, an
external time clock signal, a tenant override signal or the
unoccupied heating (night setback) and cooling (night setup
and purge) functions. Regardless of the reason it is started,
the unit always transitions through a “controlled” startup
sequence before allowing temperature control to begin.
Before Startup
Table 29: Programmable parameters
Keypad/Display ID
Parameter Name
Menu Name
Item Name
-
-
Minimum Inlet Vane
Position Limit
Timer Settings
Start Init = 3 min
Startup Initialization Timer
When the controller receives a startup command, its
operating state changes from the Off to Startup operating
state. During the Startup operating state, the Fan Operation
Output (MCB-BO3) is closed to indicate that the fans are
about to start. On VAV units with inlet vanes, the discharge
fan vanes are driven open to the non-adjustable Minimum
Inlet Vane Position Limit. This limit is 17% and is not
adjustable. The Minimum Inlet Vane Position Limit assures
that the fans do not start with a completely blocked airflow
path. On VAV units with AFDs, the AFDs remain at 0%
speed. The unit remains in the Startup operating state until
the Startup Initialization Timer expires.
CAUTION
Set the Startup Initialization Timer so the Startup operating
state lasts long enough to allow any field-supplied
equipment (such as isolation damper sets) controlled by the
Fan Operation Output (MCB-BO3) to prepare for fan
operation. Failure to do so can cause erratic operation and
equipment damage.
Fan Startup
Table 30: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Parameter Name
-
-
Airflow Check Timer
Timer Settings
Recirculate= 3 min
Recirculate State Timer
Return Air Units
The unit enters the Recirc operating state after leaving the
Startup operating state. During the Recirc operating state, the
fans are stated and operated with the outdoor air dampers
closed to allow temperature conditions throughout the unit
and space to equalize before temperature control begins.
Cooling and heating remain disabled. The VAV Box Output
(MCB-BO12) is in the open (heat) position to allow the VAV
McQuay OM-711-1
As soon as the unit leaves the Startup operating state, the
discharge fan starts and the following timers are reset and
start timing down: (1) the Airflow Check Timer, and (2) the
Recirculate State Timer.
Once the discharge fan starts, the discharge fan capacity is
modulated to maintain the duct static pressure, Bldg Static
pressure or position setpoint (VAV units).
The Fan Fail fault and the Fan Retry problem, which indicate
loss of airflow, are prevented from occurring after leaving
the Startup operating state until the Airflow Check Timer
expires. The Airflow Check Timer value is an adjustable
timer. This is to prevent nuisance unit airflow sensing related
faults (particularly on VAV units) while the airflow is
increasing.
Once in the Recirc operating state, the unit remains there
until the Recirculate State Timer expires. After the unit
leaves the Recirc operating state, the operating state entered
is a function of the current occupied/unoccupied as well as
the current temperature conditions. The Heat/Cool
Changeover section describes the heating/cooling
changeover function, which dictates whether the unit enters
a heating or the Fan Only operating state.
100% Outdoor Air Units
If the unit is equipped with a 100% outdoor air, the Recirc
operating state is bypassed and the fans are started as the unit
directly enters the Fan Only operating state after leaving the
Startup operating state.
As soon as the unit leaves the Startup operating state, the
discharge fan starts and the Airflow Check Timer is reset and
starts timing down. This timer value is an adjustable timer.
Once the discharge fan starts, the discharge fan capacity can
be modulated to maintain the duct static pressure, Bldg
Static pressure or position setpoint (VAV units).
The Fan Fail fault and the Fan Retry problem, which indicate
loss of airflow, are prevented from occurring after leaving
the Startup operating state until the Airflow Check Timer
expires. This is to prevent nuisance unit airflow sensing
related faults (particularly on VAV units) while the airflow is
increasing.
After the unit leaves the Startup operating state, the
operating state entered is a function of the current
occupied/unoccupied as well as the current temperature
conditions. The following section describes the
heating/cooling changeover function, which dictates whether
the unit enters a heating or fan only operating state.
Note: While the Airflow Check Timer is timing down and,
therefore, while the Fan Fail fault and the Fan Retry
problem alarms are being ignored, the unit will not
be allowed to enter a cooling operating state.
61
Heat/Cool Changeover
temperature sensor, when present, is the best “Control
Temperature.”
In general, a unit configured for discharge air temperature
control either operates to deliver the cooling discharge
temperature setpoint using economizer and/or mechanical
cooling or the heating discharge air temperature setpoint
using the heating equipment. Cooling and heating never
operate simultaneously. The following sections describe the
unit heat/cool changeover function.
Temperature Control
Once enabled by the “Control Temperature” cooling or
heating capacity control operates as described in
“Economizer” on page 64, “Cooling: Multistage” on page
67, “Cooling: Modulating” on page 72, “Heating:
Multistage” on page 73 or “Heating: Modulating
Temperature Control” on page 74, as applicable. The
following sections describe in detail how the “Control
Temperature” enables cooling and heating operation.
Table 31: Programmable parameters
Note: Although enabled based on the “Control
Keypad/Display ID
Menu Name
Item Name
Parameter Name
CntlTemp Src= Return
Control Temperature
Source
Eff Clg Spt= ____ °F
Effective Cooling
Enable Setpoint
Occ Clg Spt= 75.0 ºF
Cooling Enable
Setpoint
Clg Deadband= 1.0 ºF
Cooling Enable
Deadband
CntlTemp Src= Return
Control Temperature
Source
Eff Htg Spt= ____ °F
Effective Heating
Enable Setpoint
Occ Htg Spt= 70.0 ºF
Heating Enable
Setpoint
Htg Deadband= 1.0 ºF
Heating Enable
Deadband
Zone Cooling
Zone Heating
Control Temperature
The “Control Temperature” is defined as the unit temperature
input used to make the heat/cool changeover decision. This
determines whether or not cooling or heating is enabled.
Normally the return air temperature input is used as the
“Control Temperature.” Alternatively, if the unit is equipped
with modulating or multistage heat, the outdoor air
temperature input can be selected as the “Control
Temperature.” If an optional space temperature sensor is
installed, the space temperature input may be selected as the
“Control Temperature.” The current value of the “Control
Temperature” can be displayed be viewing the Ctrl Temp=
parameter in the Temperatures menu.
When the Control Temperature Source is set to “Return,” the
unit return air temperature sensor (if present) acts as the
“Control Temperature.” When the Control Temperature
Source is set to “Space,” the unit space air temperature
sensor (if present) acts as the “Control Temperature.” When
the Control Temperature Source is set to “OAT,” the outdoor
air temperature sensor acts as the “Control Temperature.”
When the control temperature source is set to “MAT,” the
unit mixed air temperature sensor acts as the “Control
Temperature.” For most applications, the return air
62
Temperature,” cooling or heating operation can be
disabled for other reasons. Refer to “Clg Status” on
page 38 and “Htg Status” on page 39.
Setpoints and Deadbands
In determining whether heating or cooling operation is
enabled, the controller compares the “Control Temperature”
input with separate cooling and heating enable setpoints.
When the “Control Temperature” is greater than the
Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband, cooling operation is enabled.
When the “Control Temperature” is below the Effective
Heating Enable Setpoint by more than half the Heating
Enable Deadband, heating operation is enabled. Separate
cooling and heating enable deadbands assure that the unit
does not cycle rapidly between cooling and heating.
When the “Control Temperature” is between the two
effective setpoints and deadbands, cooling and heating
operation are disabled and the unit runs in the Fan Only
operating state. If the unit is equipped with modulating or
multistage heat, the unit can operate the heat in this case
based on a discharge temperature low limit function if the
discharge air temperature gets too cold. Refer to “Discharge
Air Low Limit Control” on page 74 (multistage heat) or
“Discharge Air Low Limit Control” on page 75 (modulating
heat) as applicable.
The Effective Cooling Enable Setpoint and Effective
Heating Enable Setpoint are not adjustable from the keypad.
They are set equal to the Cooling Enable Setpoint and
Heating Enable Setpoint respectively.
Cooling and heating can never be simultaneously enabled
because the controller prevents the setpoints and deadbands
from being set so that the Cooling Enable Deadband and
Heating Enable Deadband overlap. In doing this, the
controller always gives the Effective Cooling Enable
Setpoint the highest priority. Regardless of whether the
cooling setpoint is lowered, the heating setpoint is raised or
either of the deadbands are raised, the controller
automatically lowers the Effective Heating Setpoint enough
to prevent the deadbands from overlapping.
McQuay OM-711-1
Illustrative Heat/Cool Changeover Sequence
The following is an illustration of the heat/cool changeover
function. Refer to Figure 8.
When the “Control Temperature” rises above the Effective
Cooling Enable Setpoint by more than half of the Cooling
Enable Deadband (Point A), cooling operation is enabled
(economizer and mechanical). Cooling operation then
remains enabled until the “Control Temperature” begins to
drop and falls below the Effective Cooling Enable Setpoint
by more than half of the Cooling Enable Deadband (Point
B), at which point cooling operation is disabled (economizer
and mechanical). The unit enters the Fan Only or MinDAT
operating state. When the “Control Temperature” drops
below the Effective Heating Enable Setpoint by more than
half of the Heating Enable Deadband (Point C), heating
operation is enabled. Heating operation then remains
enabled until the “Control Temperature” begins to rise and
rises above the Effective Heating Enable Setpoint by more
than half the Heating Enable Deadband (Point D), at which
point the unit returns to the Fan Only or MinDAT operating
state.100%
Outdoor Air Damper Control
When a unit is equipped with a 100% outdoor air control, the
outdoor air dampers are driven open continuously whenever
the unit enters the Startup operating state. If they are not
open (above 50%) at the end of the Startup operating state or
any time afterward while the fans are running, the unit is
shutdown on the OA Dmpr Stuck fault.
When the unit is shut down, the dampers remain open for 30
seconds after the unit airflow switch opens up indicating loss
of airflow.
The dampers remain open in the event that the airflow switch
does not open after the fans are shut down.
Figure 8: Illustrative heat/Cool Changeover Operating Sequence
Cooling Enabled
Effective Cooling
Enable Set Point
Control Temperature
A
}
B
D
}
}
C
Cooling Enable Dead Band
Fan Only
Heating Enable Dead Band
Effective Heating
Enable Set Point
Heating Enabled
Time
McQuay OM-711-1
63
Economizer
Economizer to Cooling Operating State
Temperature Control
Table 32: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Eff Clg Spt= ___ ºF
Effective Cooling
Enable Setpoint
Clg Deadband= 1.0 ºF
Cooling Enable
Deadband
Eff Clg Spt= ___ ºF
Effective Discharge
Cooling Setpoint
Clg Db= 1.0 ºF
Discharge Cooling
Deadband
Stage Timer= 5 min
Cooling Interstage
Timer
Clg Propbd= 30.0 ºF
Economizer Cooling
Proportional Band
Clg IntTime= 100 sec
Economizer Cooling
Integral Time
Clg Period= 30 sec
Economizer Cooling
Period
Zone Cooling
Discharge Cooling
Compressor
Setup
Economizer Setup
Parameter Name
The transition from the Econo to Cooling operating state
occurs when the economizer is unable to satisfy the cooling
load and mechanical cooling is available. Normally, this
occurs when the OA Damper Pos= parameter or Econo Pos=
parameter indicates more than 90% open and the discharge
air temperature is above the Effective Discharge Cooling
Setpoint by more than half the Discharge Cooling Deadband
for longer than the Cooling Interstage Timer.
To allow for the transition from the Econo to Cooling
operating state in the event the actuator gets stuck or there is
a problem with the actuator feedback circuit and the Econo
Pos= or OA Damper= parameter does not reach 90%, the
controller continually estimates the position. This estimate is
based on the accumulative drive open versus drive close time
compared to the nominal stroke of the actuator. If the
controller position estimate reaches 100% open and the
discharge air temperature is above the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband for longer than the Cooling Interstage Timer, the
unit makes the transition from the Econo to Cooling
operating state regardless of the current OA Damper Pos=
parameter or Econo Pos = Parameter indication.
Entering Econo Operating State
Following Applies to Airside Economizer
If a unit is equipped with a 0-100% modulating economizer,
and the conditions are suitable for free cooling as described
in “Economizer Changeover Method (Airside)” on page 65
and “Economizer Changeover Method (Waterside)” on page
65, the unit attempts to satisfy the cooling load by using the
Economizer before using mechanical cooling. In this case,
when the Ctrl Temp= parameter is above the Effective
Cooling Enable Setpoint by more than half the Cooling
Enable Deadband and the Disch Air= parameter is above the
Effective Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband, the controller enters the
Econo state.
If the OA Ambient= value changes from “Low” to “High” at
any time while the unit is in the Econo operating state, the
transition from the Econo to Cooling operating state occurs
if mechanical cooling is enabled. The outdoor air dampers
are driven to the Effective Minimum Outdoor Damper
Position Setpoint Refer to “Minimum Ventilation Control
(Airside Economizer Only)” on page 66.
When the unit is in the Econo operating state, the
Economizer is modulated as required to maintain the
Effective Discharge Cooling Setpoint.
Note: Unless it is reset via one of the discharge air setpoint
reset methods described in “Cooling Discharge
Setpoint Reset” on page 76, the Effective Discharge
Cooling Setpoint is set by the controller equal to the
Discharge Cooling Setpoint.
To modulate the Economizer, the controller uses three PID
control loop parameters as the discharge air temperature
changes. Theses are the Economizer Cooling Proportional
Band, Economizer Cooling Integral Time and Economizer
Cooling Period. Although these parameters can be adjusted,
for most applications, the factory default values for these
parameters provide the best control. For detailed information
regarding tuning PID control loop parameters, refer to
“MicroTech II DDC Features” on page 90.
64
Whenever a unit is in the Cooling operating state and the OA
Ambient= parameter indicates “Low,” the outdoor air
dampers are driven continuously open. They remain there as
long as the OA Ambient= parameter indicates “Low.” If
mechanical cooling is no longer necessary, the unit leaves
the Cooling and re-enters the Econo operating state and
damper modulation resumes.
Note: The unit remains in the Cooling operating state for at
least one Cooling Interstage Timer period.
Econo to Fan Only Operating State
The unit will leave the Econo operating state and enter the
Fan Only operating state when the Ctrl Temp= value falls
below the Effective Cooling Enable Setpoint by more than
half the Cooling Enable Deadband.
The unit will also leave the Econo operating state and enter
the Fan Only operating state if the OA Damper Pos=
parameter indicates that the outdoor dampers have been at
the Effective Minimum Outdoor Damper Position Setpoint
for one Cooling Interstage Timer period and the Disch Air=
parameter is below the Effective Discharge Cooling Setpoint
by more than half the Discharge Cooling Deadband (Airside
economizer only).
McQuay OM-711-1
The unit will also leave the Econo operating state and enter
the Fan Only operating state if all cooling is disabled for any
reason.
Economizer Changeover Method (Airside)
Table 33: Programmable parameters
Keypad/Display ID
Menu Name
OA Damper
Item Name
Parameter Name
EconChgovr=
Enthalpy
Economizer
Changeover Flag
EconChgovrT= 60 ºF
Economizer
Changeover Setpoint
EconChgovrDiff= 1ºF
Economizer
Changeover Differential
There are three methods of determining whether or not the
outdoor air is suitable for free cooling. Two of them sense
enthalpy (dry bulb temperature and humidity) and one senses
outdoor air dry bulb temperature only.
Enthalpy Changeover
The two optional enthalpy changeover methods use external
control devices. One device compares the outdoor enthalpy
with a setpoint; the other compares the outdoor air enthalpy
with the return air enthalpy. All units with economizers are
at least equipped with the outdoor air enthalpy version. The
comparative version is optional. In either case a binary input
(MCB-BI11) is delivered to the controller indicating whether
or not outdoor air is suitable for free cooling. When the
outdoor air is suitable for free cooling (MCB-BI11 on), the
OA Ambient= parameter indicates “Low” and the
economizer operates as described above in the Figure on
page 68. When the outdoor air is not suitable for free cooling
(MCB-BI11 off), the OA Ambient= parameter indicates
“High” and economizer operation is disabled.
To use either of these enthalpy methods, the Economizer
Changeover Flag must be set to “Enthalpy.” In this case, the
Economizer Changeover Setpoint is ignored.
For detailed information regarding the external enthalpy
controls, refer to the “Unit Options” section of the modelspecific installation manual (see Table 1 on page 1).
Dry Bulb Temperature Changeover
When a unit is equipped with an economizer, an internal drybulb temperature changeover strategy can be selected. When
this method is selected, the controller compares the OA
Temp= value to the Economizer Changeover Setpoint. The
enthalpy control input is ignored in this case.
To use the dry bulb method, the Economizer Changeover
Flag must be set to “Dry Bulb.” The controller then uses the
Economizer Changeover Setpoint to determine whether or
not outdoor air may be used for cooling. If the OA Temp=
value is less than or equal to this setpoint, economizer
cooling is enabled (OA Ambient= parameter indicates
“Low”). If the OA Temp= value rises above this setpoint by
McQuay OM-711-1
more than the Economizer Changeover Differential,
economizer cooling is disabled (OA Ambient= parameter
indicates “High”) and the outdoor air dampers are driven to
the Effective Minimum Outdoor Damper Position Setpoint
Refer to “Minimum Ventilation Control (Airside
Economizer Only)” on page 66.
Economizer Changeover Method
(Waterside)
Table 34: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Waterside
Economizer
EWT Diff = 3.0°F
Parameter Name
Economizer
Changeover
Differential
When a unit is equipped with a waterside economizer, free
cooling is determined by comparing the differential between
the entering water temperature and the mixed air
temperature. For free cooling to be enabled the differential
between EWT and MAT must be equal to or greater than the
EWT Diff= parameter.
Bypass Valve Control
The bypass valve to the condenser is closed in all states
except the Fan Only, Mechanical Cooling, and Economizer.
The bypass valve is opened in the Fan Only State when
cooling is required so that water flow and an accurate
entering water temperature can be determined. The bypass
valve is open in the Mechanical Cooling State when
mechanical cooling is required and water is not flowing
through the waterside economizer. The bypass valve is open
in the Economizer State if an airside economizer is installed,
the position of the economizer exceeds 90% and the
Discharge Air Temperature is greater than the Effective
Cooling Setpoint plus half the Deadband. The bypass valve
may be linked (or slaved) to the economizer valve so that the
bypass valve closes as the waterside economizer valve
opens. This provides nearly constant flow through the unit
regardless of the requirements of the economizer. The
bypass valve is open when the economizer is closed.
Water Regulating Valve Control
Table 35: Programmable parameters
Keypad/Display ID
Parameter Name
Menu Name
Head
Pressure
Item Name
HdPress
Comp1 = ___ psi
Actual Head Pressure
Compressor #1
HdPress
Comp2 = ___ psi
Actual Head Pressure
Compressor #2
Setpoint = 160
psi
Head Pressure Setpoint
65
Instead of being controlled as described in the Bypass Valve
Control section, the water flow to the condenser may be
modulated in response to refrigerant pressure signals. This
feature is only provided on units that do not have a waterside
economizer
Minimum Ventilation Control (Airside
Economizer Only)
Table 36: Programmable parameters
Keypad/Display ID
Menu Name
The Water Regulating Valve is driven closed in all states
except the Fan Only, Economizer, and Mechanical Cooling
states.
In the Fan Only state, the Water Regulating Valve is opened
for an adjustable Compressor Delay timer (Comp Delay = 30
sec) when Mechanical Cooling is required to allow water to
flow through the condenser before the compressor starts.
The Water Regulating Valve is opened for the adjustable
Comp Delay = timer in the Fan Only State if ALL of the
following are true:
• Mechanical Cooling is not disabled by any means other
than Low EWT or no water flow.
AND
• Airside Economizer operation is disabled or not installed.
AND
Item Name
Parameter Name
Eff Min OA Pos= ___%
Effective Minimum
Outdoor Damper
Position Setpoint
MinOA Pos= 10%
Minimum Outdoor
Damper Position
Setpoint
Airside
Economizer
Whenever power is applied to the controller, the outdoor air
dampers are prevented from closing below the Effective
Minimum Outdoor Damper Position Setpoint. This is to
ensure that a minimum amount of ventilation air is always
supplied to the space.
Note: During the Off, Startup, Recirc, and MWU operating
states, the Effective Minimum Outdoor Damper
Position Setpoint is set to 0%.The Effective
Minimum Outdoor Damper Position Setpoint can be
reset between the Minimum Outdoor Damper
Position Setpoint and the Effective Minimum
Outdoor Damper Position Setpoint Maximum Limit
via the keypad with the Min OA Pos= parameter or
via a network signal.
• Control Temperature > Zone Cooling Setpoint + (Zone
Cooling Deadband / 2).
Unoccupied Operation
In the Fan Only State, the Water Regulating Valve is closed
if any of the following are true:
Whenever the unit is operating in the unoccupied operating
states UnocEcon, UnocClg, or UnocHtg, the Effective
Minimum Outdoor Damper Position Setpoint is set to 0%.
• Cooling is disabled by any means other than Low EWT or
no water flow.
OR
• Airside Economizer operation is enabled.
OR
Network OA Reset
The Effective Minimum Outdoor Damper Position Setpoint
is set equal to the Minimum Outdoor Damper Position
Setpoint. The Minimum Outdoor Damper Position Setpoint
can then be set via the keypad or a network signal to meet
the outdoor air requirements.
• Control Temperature <= Zone Cooling Setpoint + (Zone
Cooling Deadband / 2)
In the Economizer State, the Water Regulating Valve is
normally closed. It is opened for the adjustable Comp Delay
= timer in the Economizer State only if the following is true:
• Economizer Position > 90.0%
AND
• Discharge Air Temperature > Eff DAT Clg Spt + (DAT Clg
Deadband / 2)
In the Mechanical Cooling State, the Water Regulating Valve
will be modulated to maintain the Head Pressure Setpoint.
The Water Regulating Valve is modulated based on the
higher of the two refrigerant pressure sensors.
66
McQuay OM-711-1
Cooling: Multistage
and the cooling capacity has been at 0% for longer than the
Cooling Interstage Timer period.
Temperature Control
Table 37: Programmable parameters
Keypad/Display ID
Menu Name
Parameter Name
Item Name
Cooling to Fan Only Operating State
Eff Clg Spt= ___ ºF
Effective Cooling
Enable Setpoint
Clg Deadband= 1.0 ºF
Cooling Enable
Deadband
Eff Clg Spt= ___ °F
Effective Discharge
Cooling Setpoint
DAT Clg Spt= 55.0 ºF
Discharge Cooling
Setpoint
Clg Db= 1.0 ºF
Discharge Cooling
Deadband
Clg Method= Nearest
Discharge Cooling
Method Flag
Stage Time= 5 min
Cooling Interstage
Timer
Zone Cooling
Discharge
Cooling
Compressor
Setup
Entering Cooling Operating State
The unit enters the Cooling operating state from the Fan
Only operating state when the Ctrl Temp= value rises above
the Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband, the Disch Air= parameter is
above the Effective Discharge Cooling Setpoint by more
than half the Discharge Cooling Deadband and economizer
operation is not available. The unit enters the Cooling
operating state from the Econo operating state as describe in
“Economizer to Cooling Operating State” on page 64.
When the unit is in the Cooling operating state, cooling
stages are turned on and off to maintain the discharge air
temperature at the Effective Discharge Cooling Setpoint.
Note: Unless it is reset via one of the discharge air setpoint
reset methods described in “Cooling Discharge
Setpoint Reset” on page 76, the Effective Discharge
Cooling Setpoint is set by the controller equal to the
Discharge Cooling Setpoint.
The controller stages compressor stages up or down as
required to maintain the discharge air temperature at the
Effective Discharge Cooling Setpoint using either the
“Nearest” or “Average” control method. The control method
is selected by setting the Discharge Cooling Method Flag.
For details regarding the “Average” and “Nearest” control
methods refer to “Nearest DAT Compressor Staging” on
page 67 or “Average DAT Compressor Staging” on page 69,
as applicable.
Cooling to Econo Operating State
The unit will transition from the Cooling to Econo operating
state if economizer operation is available when the Disch
Air= parameter is below the Effective Discharge Cooling
Setpoint by more than half the Discharge Cooling Deadband
McQuay OM-711-1
The unit will also transition from the Cooling to Econo
operating state if economizer operation is available and
compressor operation becomes disabled as described in
“Low Ambient Cooling Lockout” on page 71.
The unit will transition from the Cooling to Fan Only
operating state when economizer operation is not available,
the Disch Air= parameter is below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband and the cooling capacity has been at 0% for longer
than the Cooling Interstage Timer period.
The unit will also transition from the Cooling to Fan Only
operating state if the Ctrl Temp= parameter falls below the
Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband.
Nearest DAT Compressor Staging
A cooling stage change can only occur after the Cooling
Interstage Timer has expired and if the discharge air
temperature is above or below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband (unless the unit is shut down or when cooling is
disabled). These constraints on compressor staging are
essential for preventing short cycling, which can reduce
compressor life by causing improper oil return and excessive
heat buildup in the motor windings. After these two
conditions have been met, a stage change occurs whenever
such a change will result in the discharge air temperature
being closer to the Effective Discharge Cooling Setpoint.
This method results in fewer stage changes and hence fewer
changes in the discharge air temperature and airflow
delivered to the zones. This method may be more desirable
in an application with zones whose cooling loads can be met
with discharge air temperatures close to the Effective
Discharge Cooling Setpoint.
To determine whether or not a stage change is made, the
controller first calculates a DAT Difference. The DAT
Difference is the change in the discharge air temperature
between the time that the last stage change was made and the
Cooling Interstage Timer expires. The assumption is that the
discharge air temperature changes by this amount if the
previous stage change is reversed. The controller also
calculates a DAT Error. The DAT Error is the current
difference between the discharge air temperature and the
Effective Discharge Cooling Setpoint. If the DAT Error
equals half of the DAT Difference, a stage change should
result in a discharge air temperature on the other side of the
Effective Discharge Cooling Setpoint with the same DAT
Error. Therefore, the discharge air temperature should be
closer to the Effective Discharge Cooling Set if the DAT
Difference is less than twice the DAT Error. Compressor
staging is slightly biased to maintain the discharge air
temperature toward the low side.
67
During normal operation, the number of stages cannot
change while the discharge temperature is within the range
around the Effective Discharge Cooling Setpoint defined by
the Discharge Cooling Deadband. Typically, during periods
of constant cooling load, cooling is alternately staged up and
down between the two stages that cause the discharge air
temperature to fluctuate closely above and below the
Effective Discharge Cooling Setpoint. During periods of
increasing or decreasing cooling load, two or more
consecutive stage-up actions or stage-down actions can
occur. The following are descriptions of the four possible
consecutive stage changes when the “Nearest” control
method is active.
Point 1. Assume that the controller has just staged up
Stage-Down to Stage-Up. A stage increase occurs after a
stage decrease if all of the following are true:
Point 4. The Cooling Interstage Timer has expired. The
1. Discharge Air Temperature is above the Effective
Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband
2. Cooling Interstage Timer has expired
3. DAT Error > (DAT difference/2)
Stage-Up to Stage-Down: A stage decrease occurs after a
stage increase if all of the following are true:
1. Discharge Air Temperature is below the Effective
Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband
2. Cooling Interstage Timer has expired
3. DAT Error > (DAT difference/2)+1°F
Stage-Up to Stage-Up. A stage increase occurs after a stage
increase if both the following are true:
1. Discharge Air Temperature is still above the Effective
Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband
2. Cooling Interstage Timer has expired
Stage-Down to Stage-Down: A stage decrease occurs after
a stage decrease if both the following are true:
1. Discharge Air Temperature is still below the Effective
Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband
2. Cooling Interstage Timer has expired
cooling. As a result, the discharge air temperature begins to
drop and the Cooling Interstage Timer is reset.
Point 2. The Cooling Interstage Timer has not yet expired,
nor is the discharge air temperature below the Effective
Discharge Cooling Setpoint by more than half the Discharge
Cooling Deadband, therefore, no staging action occurs.
Point 3. The Cooling Interstage Timer has expired. The
discharge air temperature is below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband. However, the DAT Error is not greater than
[(DAT Difference/2) +1]. Therefore, no staging action is
taken.
discharge air temperature is below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband and the DAT Error is greater than [(DAT
Difference/2) +1]. Therefore, cooling is staged down one
stage. Note that the elapsed time since the last stage change
in this illustration is 7.25 minutes.
Point 5. The Cooling Interstage Timer has expired. The
discharge air temperature is below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband. Since the previous stage change was down,
cooling is again staged down a stage.
Point 6. The Cooling Interstage Timer has expired but the
discharge air temperature is within the Discharge Cooling
Deadband around the Effective Discharge Cooling Setpoint.
Therefore, no staging action is taken.
Point 7. The Cooling Interstage Timer has expired. The
discharge air temperature is above the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband, however, the DAT Error is not greater than the
DAT Difference/2. Therefore, no staging action is taken.
Point 8. The Cooling Interstage Timer has expired. The
discharge air temperature is above the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband and the DAT Error is greater than DAT
Difference/2. Therefore, cooling is staged up one stage. Note
that the elapsed time since the last stage change in this
illustration is 11.0 minutes.
Note that a stage-down from stage 1 to stage 0 can occur.
During stage 0 operation, all cooling stages are off but the
controller remains in the Cooling operating state. After the
Cooling Interstage Timer expires, another stage-down would
cause the controller to leave the Cooling operating state.
Nearest Discharge Control Method Illustration
The following is an illustration of the “Nearest” compressor
staging control method. This illustration is meant to show a
variety of staging possibilities, not normal unit operation.
Refer to Figure 9, which shows nine points on a graph of the
discharge air temperature changing with time. The Cooling
Interstage Timer setting is 5 minutes in this illustration.
68
McQuay OM-711-1
Figure 9: Nearest discharge air control method illustration
No Action
(DAT Error not
greater than
DAT Difference/2)
Stage Up
Discharge Air Temperature
1
2
3
No Action
(Within
dead band
and
Interstage
Timer not
expired)
No Action
(DAT Error not
greater than
[DAT Difference/2]+1
5
4
Stage
Down
Stage Down
(Previous
(DAT Error
change
greater than
[DAT Difference]+1) was
down)
5
8
9
7
Stage Up
(Previous
change was
up)
}
6
No Action
(Within dead
band)
Discharge Cooling
Dead Band
Effective Discharge
Cooling Set Point
}
11.0
}
7.25
Stage Up
(DAT Error
greater than
DAT
Difference/2)
5
5
5
5
Time (Minutes)
Point 9. The Cooling Interstage Timer has expired. The
discharge air temperature is above the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband. Since the previous stage change was up, cooling
is again staged up a stage.
Average DAT Compressor Staging
This staging method is useful if the average discharge air
temperature over time can be maintained at the Effective
Discharge Cooling Setpoint to meet the cooling load of one
or more spaces.
A cooling stage change can only occur after the Cooling
Interstage Timer has expired and the discharge air
temperature is above or below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband (unless the unit is shut down or cooling is
disabled). These constraints on compressor staging are
essential for preventing short cycling, which can reduce
compressor life by causing improper oil return and excessive
heat buildup in the motor windings. After these two
conditions have been met, staging occurs as the controller
attempts to equalize two running totals: degree-time above
setpoint (DTA) and degree-time below setpoint (DTB).
Approximately every 15 seconds the controller measures the
number of degrees the discharge air temperature is above the
Effective Discharge Cooling Setpoint. If above the setpoint,
each new measurement is added to a running total, named
DTA.
Approximately every 15 seconds the controller measures the
number of degrees the discharge air temperature is below the
Effective Discharge Cooling Setpoint. If below the setpoint,
each new measurement is added to a running total, named
DTB.
McQuay OM-711-1
During normal operation, the number of stages does not
change while the discharge temperature is within the range
around the Effective Discharge Cooling Setpoint defined by
the Discharge Cooling Deadband. Typically, during periods
of constant cooling load, cooling is alternately staged up and
down between the two stages that cause the discharge air
temperature to fluctuate closely above and below the
Effective Discharge Cooling Setpoint. During periods of
increasing or decreasing cooling load, two or more
consecutive stage-up actions or stage-down actions can
occur. The following are descriptions of the four possible
consecutive staging changes when “Average” control is
active.
Stage-Up to Stage-Down: After a stage-up occurs, the
discharge air temperature usually begins to drop toward
setpoint. DTA accumulates and continues to do so until the
Effective Discharge Cooling Setpoint is reached. When the
discharge air temperature drops below the Effective
Discharge Cooling Setpoint, DTA stops accumulating and
DTB starts accumulating. When DTB equals or exceeds
DTA, a stage-down occurs if the Cooling Interstage Timer
has expired and the discharge air temperature is below the
Effective Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband. (If either staging constraint
has not been met, a stage down cannot occur and DTB
continues accumulating.) After the stage-down occurs, the
DTA value is subtracted from both DTA and DTB. As a
result, DTA is zeroed and DTB is either zeroed or reduced by
the DTA amount. The Cooling Interstage Timer is reset and
degree-time accumulation resumes.
Stage-Down to Stage-Up: After a stage-down occurs, the
discharge air temperature usually begins to rise toward the
Effective Discharge Cooling Setpoint. DTB accumulates and
69
continues to do so until the Effective Discharge Cooling
Setpoint is reached. When the discharge air temperature rises
above the Effective Discharge Cooling Setpoint, DTB stops
accumulating and DTA starts accumulating. When DTA
equals or exceeds DTB, a stage-up occurs if the Cooling
Interstage Timer has expired and the discharge air
temperature is above the Effective Discharge Cooling
Setpoint by more than half the Discharge Cooling Deadband.
(If either staging constraint has not been met, a stage up
cannot occur and DTA continues accumulating.) After the
stage-up occurs, the DTB value is subtracted from both DTB
and DTA. As a result, DTB is zeroed and DTA is either
zeroed or reduced by the DTB amount. The Cooling
Interstage Timer is reset and degree-time accumulation
resumes.
Setpoint by more than half the Discharge Cooling Deadband
after the Cooling Interstage Timer expires. After the stage-up
occurs, DTA and DTB are zeroed. The Cooling Interstage
Timer is reset and degree-time accumulation resumes.
Stage-Up to Stage-Up: If the cooling load increases after a
stage-up occurs, the discharge air temperature may drop for a
while and then rise again. Regardless of the DTA and DTB
values, another stage-up occurs if the discharge air
temperature is still above the Effective Discharge Cooling
Note that a stage-down from stage 1 to stage 0 can occur.
During stage 0 operation, all cooling stages are off but the
controller remains in the Cooling operating state. After the
Cooling Interstage Timer expires, another stage-down would
cause the controller to leave the Cooling operating state.
Stage-Down to Stage-Down: If the cooling load decreases
after a stage-down occurs, the discharge air temperature may
rise for a while and then drop again. Regardless of the DTA
and DTB values, another stage-down occurs if the discharge
air temperature is still below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband after the Cooling Interstage Timer expires. After
the stage-down occurs, DTA and DTB are zeroed. The
Cooling Interstage Timer is reset and degree-time
accumulation resumes.
Figure 10: Average discharge air control method illustration
1
Stage Up
Stage Up
[(C+D=(E+F)]
5 and Interstage
Timer is expired
No Action
4
8 Stage Up
E
A
F
J
H
B
C
D
2
No Action
(A=B),
Interstage
Timer not
expired
3
Stage Down
}
6.3
5
5
K
L
I
M
6
No Action
Inside
dead band
9
Stage Down
(L=M)
}
Discharge Cooling
Dead Band
Effective Discharge
Cooling Set Point
11.3
}
Discharge Air Temperature
Stage Up 7
5
5
5
Time (Minutes)
70
McQuay OM-711-1
Average Discharge Control Method Illustration
The following is an illustration of the “Average” compressor
staging control method. This illustration is meant to show a
variety of staging possibilities, not normal unit operation.
Refer to Figure 10, which shows nine points on a graph of
the discharge air temperature changing with time. The
Cooling Interstage Timer setting is 5 minutes in this
illustration.
Point 1. Assume that the controller has just staged up and
that DTA and DTB are zero. As a result, the discharge air
temperature drops and the Cooling Interstage Timer is reset.
Point 2. DTA (Area A) equals DTB (Area B). The discharge
air temperature is below the Effective Discharge Cooling
Setpoint by more than half the Discharge Cooling Deadband.
However, since the Cooling Interstage Timer has not yet
expired, no staging action occurs.
Point 7. The discharge air temperature is again above the
Effective Discharge Cooling Setpoint by more than half the
Discharge Cooling Deadband. Since the Cooling Interstage
Timer expired at Point 6, cooling is staged up. As a result,
both DTA and DTB are zeroed and the Cooling Interstage
Timer is reset. Note that DTA and DTB are both zeroed since
two consecutive stage increase actions occurred. The
discharge air temperature continues to rise, however,
because the cooling load is still increasing. Note that the
elapsed time since the last stage change in this illustration is
11.0 minutes.
Point 8. The Cooling Interstage Timer has expired. Since the
discharge air temperature is still above the Effective
Discharge Cooling Setpoint by more than half the Discharge
Cooling Deadband, another stage-up occurs. As a result,
DTA (Area K) is again zeroed out (DTB remains zeroed) and
the Cooling Interstage Timer is reset. The cooling load has
leveled out, and the discharge air temperature drops.
Point 3. The Cooling Interstage Timer has expired. DTB
Point 9 . The Cooling Interstage Timer has expired at the
(Area B + Area C) is greater than DTA (Area A) and the
discharge air temperature is below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband. Therefore, cooling is staged down. As a result,
the discharge air temperature rises, the Cooling Interstage
Timer is reset, and DTA is subtracted from both DTA and
DTB. This zeros DTA and leaves DTB equal to Area C.
same time that DTB (Area M) becomes equal to DTA (Area
L). Therefore, cooling is staged down, the Cooling Interstage
Timer is reset and DTA is subtracted from both DTA and
DTB. This zeros both DTA and DTB since they are equal.
Point 4. The Cooling Interstage Timer has expired. The
discharge air temperature is above the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband. However, since DTA (Area E) is not yet equal to
DTB (Area C + Area D), no staging action occurs and the
discharge air temperature continues to rise.
Point 5. The Cooling Interstage Timer has expired. The
discharge air temperature is above the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband and DTA (Area E + Area F) is equal to DTB
(Area C + Area D). Therefore, cooling is staged up. As a
result, the discharge air temperature drops, the Cooling
Interstage Timer is reset, and DTB is subtracted from both
DTB and DTA. This zeros both DTA and DTB since they are
equal. Note that the elapsed time since the last stage change
in this illustration is 6.3 minutes.
Point 6. The Cooling Interstage Timer has expired. Because
the cooling load is now increasing, the discharge air
temperature does not fall below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband. No staging action occurs for two reasons: (1) the
discharge air temperature is within the Discharge Cooling
Deadband and (2) DTB (Area H) is not yet equal to DTA
(Area G). Even if the discharge air temperature falls below
the Effective Discharge Cooling Setpoint by more than half
the Discharge Cooling Deadband (as shown just after Point
6), a stage down does not occur because DTB remains less
than DTA. The discharge air temperature starts rising again
because the load is increasing.
McQuay OM-711-1
Low Ambient Cooling Lockout
Table 38: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
OATClg Lock= 55.0 ºF
Zone Cooling
OATLock Diff= 1.0 ºF
Parameter Name
Low Ambient
Cooling Lockout
Setpoint
Low Ambient
Cooling Lockout
Setpoint Differential
Mechanical cooling is disabled with the outdoor air
temperatuare is below the Low Ambient Cooling Lockout
Setpoint. When this occurs, the Clg Status= parameter
indicates either “Econo” or “Off Amb” if all cooling is not
disabled for some other reason. When the outdoor air
temperature rises above the Low Ambient Cooling Lockout
Setpoint by more than the Low Ambient Cooling Lockout
Differential, compressorized cooling is re-enabled. The Clg
Status= parameter indicates either “All Clg” or “Mech Clg”
if all cooling is not disabled for some other reason.
Compressor Staging
On units equipped with compressorized cooling, there are
many different compressor staging configurations available,
depending upon unit size. For specific output staging
information for the possible configurations, refer to the
“Cooling Control Boards (CCB1 & CCB2)” section of IM
710, MicroTech Vertical Self-Contained Systems Unit
Controller.
2-Compressors/2-Stages
There are two equally sized compressors and two
independent cooling circuits. The unit capacity is increased
71
or decreased by turning compressors on and off. One of the
compressors is designated the “Lead” and the other the
“Lag.” The compressor with the fewest run hours is staged
on first and turned off last. When a capacity increase is
required and the cooling capacity is 0%, the “Lead”
compressor is staged on. When further capacity is required,
the “Lag” compressor is staged on. Disabled compressors
are not turned on.
3-Compressors/3-Stages
There are three equally sized compressors and three
independent cooling circuits. The unit capacity is increased
or decreased by turning on and off compressors. One of the
compressors is designated the “Lead” and the others the
“Lag.” When a capacity increase is required and the cooling
capacity is 0%, the “Lead” compressor is staged on. When
further capacity is required, a “Lag” compressor with the
least operating hours of the remaining two is staged on.
When further capacity increase is required, the remaining
“Lag” compressor is staged on. When a capacity decrease is
required, the “Lag” compressor with the most hours is turned
off. When a further capacity decrease is required, the
remaining “Lag” compressor is turned off. When a further
capacity decrease is required, the “Lead” compressor is
staged off.
4-Compressors/4-Stage
There are four equally sized compressors and four
independent cooling circuits. The unit capacity is increased
or decreased by turning compressors on and off.
Compressors #1 and #2 provide the first two stages of
cooling. The compressor with the fewest run hours is staged
on first and turned off last. Compressors #3 and #4 provide
the last two stages of cooling. The compressor with the
fewest run hours is staged on first and turned off last.
Disabled compressors are not turned on.
2-Small Compressors and 2-Large
Compressors/6-Stage
There are two equally sized small compressors and two
equally sized large compressors. Each compressor is on an
independent cooling circuit. The unit capacity is increased or
decreased by staging compressors on and off. The small
compressors #1 or #2 provide the first stage of cooling. The
compressor with the fewest run hours is staged on first and
staged off last. The second stage of cooling turns on the
remaining small compressor (#1 or #2). The third stage of
cooling turns off either #1 or #2 and stages on either #3 or
#4. The third stage has one small and one large compressor
operating. The fourth stage of cooling stages on the
remaining small compressor. The fifth stage of cooling turns
off one of the small compressors and stages on the remaining
large compressor. If further cooling is required, the
remaining small compressor is staged on to provide the sixth
stage of cooling. Disabled compressors are ignored. The next
enabled compressor in the sequence is turned on when one or
more compressors are disabled and a stage up is required.
6-Compressors/6-Stage
There can be either six equally sized compressors or three
smaller and three larger sized compressors. Each compressor
is on an independent cooling circuit. The unit capacity is
increased or decreased by turning on and off compressors.
Compressors #1, #2 or #3 provide the first three stages of
cooling. The compressor with the fewest run hours is staged
on first and staged off last. Compressors #4, #5 or #6 provide
the last three stages of cooling. The compressor with the
fewest run hours is staged on first and staged off last.
Disabled compressors are not turned on.
Cooling: Modulating
Temperature Control
3-Small Compressors and 1-Large
compressor/5-Stage
There are three equally sized small compressors and one
large compressor. Each compressor is on an independent
cooling circuit. The unit capacity is increased or decreased
by staging compressors on and off. Compressors #1 or #2
provide the first stage of cooling. Compressor #1 and #2
provide the second stage. The compressor with the fewest
run hours is staged on first and staged off last. When further
capacity is required, an operating small compressor is turned
off and the large compressor is staged on to provide the third
stage of cooling. When further capacity is required,
Compressors #1 or #2 will provide the fourth stage of
cooling. Compressor #3 provides the last stage of cooling.
Note: Stages 3 and 4 are skipped when the large compressor
is disabled. The next enabled small compressor in the
sequence is staged on when one or more of the small
compressors is disabled and a stage up is required.
72
Table 39: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Eff Clg Spt= ___ ºF
Zone Cooling
Clg Deadband= 1.0
ºF
Eff Clg Spt= ___ ºF
Discharge
Cooling
DAT Clg Spt= 55°F
Clg Db= 1.0 ºF
Clg Propbd= 30.0 ºF
Chilled Water
Setup
Clg IntTime= 100 sec
Clg Period= 30 sec
Stage Timer= 5 min
Parameter Name
Effective Cooling
Enable Setpoint
Cooling Enable
Deadband
Effective Discharge
Cooling Setpoint
Discharge Cooling
Setpoint
Discharge Cooling
Deadband
Cooling
Proportional Band
Cooling Integral
Time
Cooling Period
Cooling Interstage
Timer
McQuay OM-711-1
Entering Cooling Operating State
The unit enters the Cooling operating state from the Fan
Only operating state when the Ctrl Temp= value rises above
the Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband, the Disch Air= parameter is
above the Effective Discharge Cooling Setpoint by more
than half the Discharge Cooling Deadband and economizer
operation is not available. The unit enters the Cooling
operating state from the Econo operating state as describe in
“Economizer to Cooling Operating State” on page 64.
When the unit is in the Cooling operating state, cooling
capacity is modulated to maintain the discharge air
temperature at the Effective Discharge Cooling Setpoint.
temperature condition. For example, if actual occupancy is at
8:00 a.m. and unit startup is scheduled for 6:30 a.m., a
Maximum Morning Warm-up Timer setting of 90 minutes
would ensure that the outdoor air dampers open to minimum
position when building occupancy occurs.
Heating: Multistage
Temperature Control
Table 40: Programmable parameters
Keypad/Display ID
Menu Name
Note: Unless it is reset via one of the discharge air setpoint
reset methods described in “Cooling Discharge
Setpoint Reset” on page 76, the Effective Discharge
Cooling Setpoint is set by the controller equal to the
Discharge Cooling Setpoint.Chilled Water: Valve
Control
When a unit is equipped with chilled water cooling and is in
the Cooling operating state, the chilled water valve is
modulated to maintain the discharge air temperature at the
Effective Discharge Cooling Setpoint. The controller
modulates the chilled water valve using three PID control
loop parameters to modulate the valve as the discharge air
temperature changes. Theses are the Cooling Proportional
Band, Cooling Integral Time and Cooling Period. Although
these parameters can be adjusted, for most applications, the
factory default values for these parameters provide the best
control. For detailed information regarding tuning PID
control loop parameters, refer to“MicroTech II DDC
Features” on page 90.
Cooling to Econo Operating State
The unit will transition from the Cooling to Econo operating
state if economizer operation is available when the Disch
Air= parameter is below the Effective Discharge Cooling
Setpoint by more than half the Discharge Cooling Deadband
and the chilled water valve has been closed for longer than
the Cooling Interstage Timer period.
Cooling to Fan Only Operating State
The unit will transition from the Cooling to Fan Only
operating state when economizer operation is not available,
the Disch Air= parameter is below the Effective Discharge
Cooling Setpoint by more than half the Discharge Cooling
Deadband and the chilled water valve has been closed for
longer than the Cooling Interstage Timer period.
The unit will also transition from the Cooling to Fan Only
operating state if the Ctrl Temp= parameter falls below the
Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband.
The Maximum Morning Warm-up Timer parameter is
provided to ensure that the required minimum ventilation air
is being supplied after a known time regardless of the space
McQuay OM-711-1
Item Name
Eff Htg Spt= ____ °F
Effective Heating
Enable Setpoint
Htg Deadband= 1.0 ºF
Heating Enable
Deadband
Eff Htg Spt= ___ °F
Effective Discharge
Heating Setpoint
DAT Htg Spt= 55.0 ºF
Discharge Heating
Setpoint
Htg Db= 1.0 ºF
Discharge Heating
Deadband
Stage Time= 10 Min
Heating Interstage
Timer
Zone Heating
Discharge
Heating
Heating Setup
Parameter Name
Entering Heating Operating State
The unit enters the Heating operating state from the Recirc
or Fan Only operating state when the Ctrl Temp= value falls
below the Effective Heating Enable Setpoint by more than
half the Heating Enable Deadband, and the Disch Air=
parameter is below the Effective Discharge Heating Setpoint
by more than half the Discharge Heating Deadband
When the unit is in the Heating operating state, heating
stages are turned on and off to maintain the discharge air
temperature at the Effective Discharge Heating Setpoint.
Note: Unless it is reset via one of the discharge air setpoint
reset methods described in “Heating Discharge
Setpoint Reset” on page 79, the Effective Discharge
Heating Setpoint is set by the controller equal to the
Discharge Heating Setpoint.
A heating stage change can only occur after the Heating
Interstage Timer has expired and if the discharge air
temperature is above or below the Effective Discharge
Heating Setpoint by more than half the Discharge Heating
Deadband. When the discharge air temperature is below the
Effective Discharge Heating Setpoint by more than half the
Discharge Heating Deadband and the Heating Interstage
Timer has expired, the heating capacity is increased by one
stage. When the discharge air temperature is above the
Effective Discharge Heating Setpoint by more than half the
Discharge Heating Deadband and the Heating Interstage
Timer has expired, the heating capacity is decreased by one
stage.
73
Heating to Fan Only Operating State
Heating: Modulating Temperature Control
The unit will transition from the Heating to Fan Only
operating state when the Disch Air= parameter is above the
Effective Discharge Heating Setpoint by more than half the
Discharge Heating Deadband and the heating capacity has
been at 0% for longer than the Heating Interstage Timer
period.
Table 42: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Eff Htg Spt= ___ ºF
Zone Heating
Htg Db= 1.0 °F
Eff Htg Spt= ___ ºF
The unit will also transition from the Heating to Fan Only
operating state if the Ctrl Temp= parameter rises above the
Effective Heating Enable Setpoint by more than half the
Heating Enable Deadband.
The unit will also transition from the Heating to Fan Only
operating state if heating operation is disabled as described
in “High Ambient Heating Lockout” on page 75.
Discharge Air Low Limit Control
Table 41: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Discharge
Cooling
Discharge
Heating
Eff Clg Spt= 55.0 ºF
Clg Db= 1.0 ºF
Min DAT Ctrl= Yes
Parameter Name
Effective Discharge
Cooling Setpoint
Discharge Cooling
Deadband
Min DAT Control Flag
If heating is enabled and there is no heating load (normally
Fan Only operating state), the controller activates the unit
staged electric heating equipment as required to prevent the
discharge air temperature from becoming too cool if the Min
DAT Control Flag is set to “Yes.” If the discharge air
temperature falls below the Effective Discharge Cooling
Setpoint by more than half the Discharge Cooling Deadband,
the unit operating state changes from Fan Only to Min DAT.
Because there is no actual overall heating load, the VAV Box
Output (MCB-BO12) remains closed (cool) during the Min
DAT operating state. The closed VAV Box Output can be
used to signal heat/cool VAV boxes that the unit is delivering
air at the cooling setpoints. Except for controlling to the
Effective Discharge Cooling versus Heating Setpoint, Min
DAT temperature control is identical to the Heating
operating state.
The Min DAT operating state is very useful for applications
requiring high minimum outdoor air amounts to satisfy
indoor air quality requirements. If the outdoor air
temperature is very cold, the discharge air temperature could
become unacceptably cold in these units. Because the
economizer dampers maintain their minimum position
during the Min DAT operating state, minimum ventilation
requirements are met.
74
Discharge
Heating
DAT Htg Spt= 100 °F
Htg Db= 1.0 ºF
Min DAT Ctrl= Yes
Stage Timer= 10 min
Heating Setup
Htg Propbd= 20.0 ºF
Htg IntTime= 240 sec
Htg Period= 10 sec
Discharge
Cooling
Eff Clg Spt= ___ ºF
Parameter Name
Effective Heating
Enable Setpoint
Heating Enable
Deadband
Effective Discharge
Heating Setpoint
Discharge Heating
Setpoint
Discharge Heating
Deadband
Min DAT Control Flag
Heating Interstage
Timer
Heating Proportional
Band
Heating Integral Time
Heating Period
Effective Discharge
Cooling Setpoint
Entering Heating Operating State
The unit enters the Heating operating state from the Recirc or
Fan Only operating state when the Ctrl Temp= value falls
below the Effective Heating Enable Setpoint by more than
half the Heating Enable Deadband, the Disch Air= parameter
is below the Effective Discharge Heating Setpoint by more
than half the Discharge Heating Deadband.
When the unit is in the Heating operating state, heating
capacity is modulated to maintain the discharge air
temperature at the Effective Discharge Heating Setpoint.
Note: Unless it is reset via one of the discharge air setpoint
reset methods described in “Heating Discharge
Setpoint Reset” on page 79, the Effective Discharge
Heating Setpoint is set by the controller equal to the
Discharge Heating Setpoint.
There are several different modulating heating types
available with this equipment. There are some differences in
the control sequence depending on the heat type installed.
The different types are described in the following sections.
Steam or Hot Water Heat: Valve Control
When a unit equipped with steam or hot water heating is in
the Heating operating state, the steam or hot water valve is
modulated to maintain the discharge air temperature at the
Effective Discharge Heating Setpoint. The controller uses
three PID control loop parameters to modulate the hot water
or steam valve as the discharge air temperature changes—the
Heating Proportional Band, Heating Integral Time and
Heating Period. These parameters can be adjusted, but the
factory default valves provide the best control for most
applications. For detailed information on turning PID control
loop parameters, refer to “MicroTech II DDC Features” on
page 90.
McQuay OM-711-1
Heating to Fan Only Operating State
The unit will transition from the Heating to Fan Only
operating state when the Disch Air= parameter is above the
Effective Discharge Heating Setpoint by more than half the
Discharge Heating Deadband and the heating valve has been
closed for longer than the Heating Interstage Timer period.
The unit will also transition from the Heating to Fan Only
operating state if the Ctrl Temp= parameter rises above the
Effective Heating Enable Setpoint by more than half the
Heating Enable Deadband.
The unit will also transition from the Heating to Fan Only
operating state if heat operation is disabled as described in
“High Ambient Heating Lockout” on page 75.
Morning Warm-up Control
Table 43: Programmable parameters
Keypad/Display ID
Menu Name
Zone
Heating
Timer
Settings
Item Name
Parameter Name
CntlTemp Src= Return
Control Temperature
Source
Eff Htg Spt= ____ °F
Effective Heating Enable
Setpoint
Occ Htg Spt= 70.0 ºF
Heating Enable Setpoint
Htg Deadband= 1.0 ºF
Heating Enable Deadband
Max MWU= 90 min
Maximum Morning Warmup Timer
On return air units, morning warm up operation occurs after
the transition from unoccupied to occupied mode when the
Ctrl Temp= value is below Effective Heating Enable
Setpoint by more than half the Heating Enable Deadband.
Under these conditions, the controller enters the MWU
operating state after the normal startup sequence.
Note: The morning warm-up function does not occur on
units equipped with 100% OA hoods.
High Ambient Heating Lockout
Table 44: Programmable Parameters
Keypad/Display ID
Menu Name
Zone
Heating
Item Name
Parameter Name
OATHtg Lock= 55.0 ºF
High Ambient Heating
Lockout Setpoint
OATLock Diff= 1.0 °F
High Ambient Heating
Lockout Differential
Heating is disabled whenever the outdoor air temperature is
greater than the High Ambient Heating Lockout Setpoint.
When this occurs, the Htg Status= parameter in the System
and Zone Heating menu indicates “Off Amb” if heating is
not disabled for some other reason. When the outdoor air
temperature drops below the High Ambient Heating Lockout
Setpoint by more than the High Ambient Heating Lockout
Differential, heating operation is re-enabled.
Discharge Air Low Limit Control
Table 45: Programmable parameters
Keypad/Display ID
Menu Name
Discharge
Cooling
Discharge
Heating
Item Name
Parameter Name
Eff Clg Spt= 55.0 ºF
Effective Discharge
Cooling Setpoint
Clg Db= 1.0 ºF
Discharge Cooling
Deadband
Min DAT Ctrl= Yes
Min DAT Control Flag
The MWU operating state is similar to the Heating state; the
only difference is that the Eff Min OA Pos= parameter is set
to 0% during MWU. The unit remains in the MWU state
until either the Ctrl Temp= value is equal to or greater than
the Effective Heating Enable Setpoint or the duration of the
MWU state exceeds the Maximum Morning Warm-up
Timer. In either case, since the Ctrl Temp= value has not
risen above the Effective Heating Enable Setpoint by more
than half the Heating Enable Deadband when this occurs, the
controller enters the Heating operating state.
If heating is enabled and there is no heating load (normally
Fan Only state), the controller activates the unit modulating
heating equipment as required to prevent the discharge air
temperature from becoming too cool if the Min DAT Control
Flag is set to “Yes.” If the discharge air temperature falls
below the Effective Discharge Cooling Setpoint by more than
half the Discharge Cooling Deadband, the unit operating state
changes from Fan Only to Min DAT. Because there is no
actual overall heating load, the VAV Box Output (MCBBO12) remains closed (cool) during the Min DAT state. The
closed VAV Box Output can be used to signal heat/cool VAV
boxes that the unit is delivering air at the cooling setpoints.
Except for controlling to the Effective Discharge Cooling
Setpoint rather than the Effective Discharge Heating
Setpoint, Min DAT temperature control is identical to that for
the Heating state.
The Maximum Morning Warm-up Timer parameter is
provided to ensure that the required minimum ventilation air
is being supplied after a known time regardless of the space
temperature condition. For example, if actual occupancy is at
8:00 a.m. and unit startup is scheduled for 6:30 a.m., a
Maximum Morning Warm-up Timer setting of 90 minutes
would ensure that the outdoor air dampers open to minimum
position when building occupancy occurs.
The Min DAT operating state is very useful for applications
that require large amounts of minimum outdoor air to
accommodate indoor air quality requirements. If the outdoor
air temperature is very cold, the discharge air temperature
could otherwise become unacceptably cold in these units.
Because the economizer dampers maintain their minimum
position during the Min DAT state, minimum ventilation
requirements are not violated.
Note: The Effective Heating Enable Setpoint is set by the
controller equal to the Heating Enable Setpoint.
McQuay OM-711-1
75
Discharge Setpoint Reset
Cooling Discharge Setpoint Reset
Table 46: Programmable parameters
Keypad/Display ID
Menu Name
Discharge
Cooling
Item Name
Parameter Name
not have a return air temperature sensor and,
therefore, “Return” cannot be selected.
When the Cooling Reset Type Flag is set to “OAT,” the
Effective Discharge Cooling Setpoint is reset based on the
current outdoor air temperature input.
Note: The Cooling Reset Type Flag reverts to “None” if the
Eff Clg Spt= ___ °F
Effective Discharge
Cooling Setpoint
DA Clg Spt= 55.0 ºF
Discharge Cooling
Setpoint
Min Clg Spt= 55.0 ºF
Minimum Discharge
Cooling Setpoint
Max Clg Spt= 65.0 ºF
Maximum Discharge
Cooling Setpoint
Clg Reset= None
Cooling Reset Type Flag
Min Clg Spt@= 90
Minimum Cooling Setpoint
Reset Value
Max Clg Spt@= 70
Maximum Cooling Setpoint
Reset Value
By automatically varying the discharge air temperature to
suit the cooling load, discharge air temperature reset can
make discharge air control systems more energy efficient. A
variety of reset strategies are available (some require field
wiring).
The Effective Discharge Cooling Setpoint can be reset
between the Minimum Discharge Cooling Setpoint and
Maximum Discharge Cooling Setpoint in a number of ways.
These are described as follows:
No Discharge Temperature Reset
When the Cooling Reset Type Flag is set to “None,” the
Effective Discharge Cooling Setpoint is set equal to the
Discharge Cooling Setpoint.
Temperature Based Discharge Temperature
Reset
The Effective Discharge Cooling Setpoint can be reset in
response to three temperature sensor inputs: space, return air,
or outdoor air. When any of these methods are used, the
Effective Discharge Cooling Setpoint is determined based on
the selected temperature sensor input.
When the Cooling Reset Type Flag is set to “Space,” the
Effective Discharge Cooling Setpoint is reset based on the
current space air temperature input. The space temperature
sensor is optional and must be present to allow for reset
based on space temperature.
Note: The Cooling Reset Type Flag reverts to “None” if the
Space Sensor problem occurs or if the Space Sensor=
parameter in the Unit Configuration menu is set to
“No.”
When the Cooling Reset Type Flag is set to “Return,” the
Effective Discharge Cooling Setpoint is reset based on the
current return air temperature input.
76
Note: A unit equipped with the 100% OA hood option does
OAT Sensor problem occurs.
An example of discharge temperature reset based on outdoor
air temperature is illustrated in Figure Figure 11 on page 77
(Cooling Reset Type Flag is set to “OAT” in this example).
When the current outdoor air temperature is greater than or
equal to the Minimum Cooling Setpoint Reset Value (90°F
in this example), the Effective Discharge Cooling Setpoint is
set equal to the Minimum Discharge Cooling Setpoint (55°F
in this example). This is shown as Point C in Figure 11 on
page 77. When the current outdoor air temperature is less
than or equal to the Maximum Cooling Setpoint Reset Value
(70°F in this example), the Effective Discharge Cooling
Setpoint is set equal to the Maximum Discharge Cooling
Setpoint (65 °F in this example). This is shown as Point A in
Figure 11 on page 77. When the current outdoor air
temperature is between the Minimum Cooling Setpoint
Reset Value and the Maximum Cooling Setpoint Reset
Value, the Effective Discharge Cooling Setpoint varies
linearly between the Minimum Discharge Cooling Setpoint
and Maximum Discharge Cooling Setpoint. This is shown as
Point B in Figure 11 on page 77.
Note: The Minimum Cooling Setpoint Reset Value and
Maximum Cooling Setpoint Reset Value are
displayed on the keypad/display without engineering
units. The values represent temperature (°F or °C)
when the Cooling Reset Type Flag is set to “Space,”
“Return,” or “OAT.” The values represent percentage
(%) when the Cooling Reset Type Flag is set to “Ext
mA,” “Ext V” or “Airflow.”
Airflow Based Discharge Temperature Reset
The Effective Discharge Cooling Setpoint can be reset based
on the discharge fan airflow capacity. Discharge fan capacity
reset is used when the Cooling Reset Type Flag is set to
“Airflow.”
An example of discharge temperature reset based on airflow
is illustrated in Figure 12 on page 77. When the discharge
fan capacity is greater than or equal to the Minimum Cooling
Setpoint Reset Value (100% in this example), the Effective
Discharge Cooling Setpoint is set equal to the Minimum
Discharge Cooling Setpoint. This is shown as Point C in
Figure 12 on page 77 When the discharge fan capacity is less
than or equal to the Maximum Cooling Setpoint Reset Value
(30% in this example), the Effective Discharge Cooling
Setpoint is set equal to the Maximum Discharge Cooling
Setpoint. This is shown as Point A in Figure 12 on page 77.
When the discharge fan capacity is between the Minimum
Cooling Setpoint Reset Value and the Maximum Cooling
McQuay OM-711-1
displayed on the keypad/display without engineering
units. The values represent temperature (°F or °C)
when the Cooling Reset Type Flag is set to “Space,”
“Return” or “OAT.” The values represent percentage
(%) when the Cooling Reset Type Flag is set to “Ext
mA,” “Ext V” or “Airflow.”
Setpoint Reset Value, the Effective Discharge Cooling
Setpoint varies linearly between the Minimum Discharge
Cooling Setpoint and Maximum Discharge Cooling
Setpoint. This is shown as Point B in Figure 12.
Note: The Minimum Cooling Setpoint Reset Value and
Maximum Cooling Setpoint Reset Value are
Effective Discharge Cooling Set Point
Figure 11: Discharge temperature reset based on temperature
Maximum Discharge
Cooling Set Point = 65°F
A
B
60°F
C
Maximum Cooling
Set Point Reset
Value
60
Minimum Discharge
Cooling Set Point = 55°F
Minimum Cooling
Set Point Reset
Value
70
80
90
100
OA Temperature (°F)
Effective Discharge Cooling Set Point
Figure 12: Discharge temperature reset based on discharge fan airflow
MaximumDischarge
Cooling Set Point = 65°F
A
B
60°F
C
Maximum Cooling
Set Point Reset
Value
Minimum Discharge
Cooling Set Point = 55°F
Minimum Cooling
Set Point Reset
Value
30
65
100
Discharge Fan Capacity (%)
McQuay OM-711-1
77
The Effective Discharge Cooling Setpoint can be reset based
on a field supplied analog voltage or current signal. This
signal can be in the range of 0-10 VDC or 0-20 mA. When
the Cooling Reset Type Flag is set to “Ext V” or “Ext mA,”
the Effective Discharge Cooling Setpoint varies linearly
between the Minimum Discharge Cooling Setpoint and the
Maximum Discharge Cooling Setpoint as the field voltage or
current signal varies between a minimum and maximum (or
maximum and minimum) value.
The range and type of field reset signal is configured using
the Minimum Cooling Setpoint Reset Value and the
Maximum Cooling Setpoint Reset Value and setting a
jumper on the main control board associated with analog
input MCB-AI02. The analog input jumper is placed in
either the “voltage” or “current” position. When it is in the
“voltage” position, the range of the input signal can be from
0-10 VDC and when in the “current” position, 0-20 mA. The
input range is scaled using the Minimum Cooling Setpoint
Reset Value and the Maximum Cooling Setpoint Reset Value
parameters. If for example, the field signal is to be 1-5 VDC,
the Minimum Cooling Setpoint Reset Value must be set to 10
(10%) since 1 VDC is 10% of the 0-10 VDC range. The
Maximum Cooling Setpoint Reset Value must be set to 50
(50%) since 5 VDC is 50% of the 0-10 VDC range.
Refer to “External Discharge Air Reset Signal” in the “Field
Wiring” section of IM 710, MicroTech Vertical SelfContained Unit Controller.
Reset based on an external signal can be “direct acting”
where the Effective Discharge Cooling Setpoint increases as
the field signal increases or it can be “reverse acting” where
the Effective Discharge Cooling Setpoint decreases as the
field signal increases. The following are examples of both
“direct acting” and “reverse acting” reset.
An example of “direct acting” discharge temperature reset
based on an external 1- 5 VDC signal is illustrated in
Figure 13. When the external voltage signal is less than or
equal to the Minimum Cooling Setpoint Reset Value (10% or
1 VDC in this example), the Effective Discharge Cooling
Setpoint is set equal to the Minimum Discharge Cooling
Setpoint (55 °F in this example). This is shown as Point A in
Figure 13. When the external voltage signal is greater than or
equal to the Maximum Cooling Setpoint Reset Value (50%
or 5 VDC in this example), the Effective Discharge Cooling
Setpoint is set equal to the Maximum Discharge Cooling
Setpoint (65 °F in this example). This is shown as Point C in
Figure 13. When the external voltage signal is between the
Minimum Cooling Setpoint Reset Value and the Maximum
Cooling Setpoint Reset Value, the Effective Discharge
Cooling Setpoint increases linearly between the Minimum
Discharge Cooling Setpoint and Maximum Discharge
Cooling Setpoint. This is shown as Point B in Figure 13.
Figure 13: Direct acting external reset
Effective Discharge Cooling Set Point
External Discharge Temperature Reset
C
60°F
Minimum
Discharge
Cooling Set
Point = 55°F
B
Maximum
Discharge
Cooling Set
Point = 65°F
A
Minimum Cooling
Set Point Reset
Value (10%)
Maximum Cooling
Set Point Reset
Value (50%)
5
1 3
External Signal (Vdc)
An example of “reverse acting” discharge temperature reset
based on an external 1- 5 VDC signal is illustrated in
Figure 14 on page 82. When the external voltage signal is
less than or equal to the Maximum Cooling Setpoint Reset
Value (10% or 1 VDC in this example), the Effective
Discharge Cooling Setpoint is set equal to the Maximum
Discharge Cooling Setpoint (65°F in this example). This is
shown as Point A in Figure 14 on page 79. When the
external voltage signal is greater than or equal to the
Minimum Cooling Setpoint Reset Value (50% or 5 VDC in
this example), the Effective Discharge Cooling Setpoint is
set equal to the Minimum Discharge Cooling Setpoint (55°F
in this example). This is shown as Point C in
Figure Figure 14 on page 79. When the external voltage
signal is between the Maximum Cooling Setpoint Reset
Value and the Minimum Cooling Setpoint Reset Value, the
Effective Discharge Cooling Setpoint decreases linearly
between the Maximum Discharge Cooling Setpoint and
Minimum Discharge Cooling Setpoint. This is shown as
Point B in Figure Figure 14 on page 79.
Note: The Minimum Cooling Setpoint Reset Value and
Maximum Cooling Setpoint Reset Value are
displayed on the keypad/display without engineering
units. The values represent temperature (°F or °C)
when the Cooling Reset Type Flag is set to “Space,”
“Return” or “OAT.” The values represent percentage
(%) when the Cooling Reset Type Flag is set to “Ext
mA,” “Ext V” or “Airflow.”
If the field signal exceeds 10 VDC, the cooling reset type
flag reverts to “None” and setpoint reset is disabled.
78
McQuay OM-711-1
Effective Discharge Cooling Set Point
Figure 14: Reverse acting external reset
Maximum
Discharge
Cooling Set
Point = 65°F
No Discharge Temperature Reset
When the Heating Reset Type Flag is set to “None,” the
Effective Discharge Heating Setpoint is set equal to the
Discharge Heating Setpoint.
A
B
Temperature Based Discharge Temperature
Reset
60°F
C
Maximum Cooling
Set Point Reset
Value (10%)
Minimum
Discharge
Cooling Set
Point = 55°F
Minimum Cooling
Set Point Reset
Value (50%)
5
1
3
External Signal (Vdc)
The Effective Discharge Heating Setpoint can be reset in
response to three temperature sensor inputs: space, return air,
or outdoor air. When any of these methods are used, the
Effective Discharge Heating Setpoint is determined based on
the selected temperature sensor input.
When the Heating Reset Type Flag is set to “Space,” the
Effective Discharge Heating Setpoint is reset based on the
current space air temperature input. The space temperature
sensor is optional and must be present to allow for reset
based on space temperature.
Note: The Heating Reset Type Flag reverts to “None” if the
Network Discharge Temperature Reset
When the Cooling Reset Type Flag is set to “None,” the
Effective Discharge Cooling Setpoint is set equal to the
Discharge Cooling Setpoint. The Discharge Cooling
Setpoint can then be set via a network signal to meet the
discharge air temperature requirements.
Heating Discharge Setpoint Reset
Table 47: Programmable parameters
Keypad/Display ID
Menu Name
Discharge
Heating
Item Name
Parameter Name
Eff Htg Spt= ___ °F
Effective Discharge
Heating Setpoint
DA Htg Spt= 100.0 ºF
Discharge Heating
Setpoint
Min Htg Spt= 60.0 ºF
Minimum Discharge
Heating Setpoint
Max Htg Spt= 120.0 ºF
Maximum Discharge
Heating Setpoint
Htg Reset= None
Heating Reset Type Flag
Min Htg Spt@= 60.0
Minimum Heating
Setpoint Reset Value
Max Htg Spt@= 20.0
Maximum Heating
Setpoint Reset Value
Space Sensor problem occurs or if the Space Sensor=
parameter in the Unit Configuration menu is set to
“No.”
When the Heating Reset Type Flag is set to “Return,” the
Effective Discharge Heating Setpoint is reset based on the
current return air temperature input.
Note: A unit equipped with the 100% OA hood option does
not have a return air temperature sensor and,
therefore, “Return” cannot be selected.
When the Heating Reset Type Flag is set to “OAT,” the
Effective Discharge Heating Setpoint is reset based on the
current outdoor air temperature input.
Note: The Heating Reset Type Flag reverts to “None” if the
OAT Sensor problem occurs.
• The heating discharge setpoint can be reset in all heating
configurations. By automatically varying the discharge air
temperature to suit the heating load, discharge air
temperature reset can make discharge air control systems
more energy efficient. A variety of reset strategies are
available (some require field wiring).
• The Effective Discharge Heating Setpoint can be reset
between the Minimum Discharge Heating Setpoint and
Maximum Discharge Heating Setpoint in a number of
ways.
McQuay OM-711-1
79
Effective Discharge Heating Set Point
Figure 15: Discharge temperature reset based on temperature
Maximum Discharge
Heating Set Point = 120°F
A
B
90°F
C
Maximum Heating
Set Point Reset
Value
0
Minimum Discharge
Heating Set Point = 60°F
Minimum Heating
Set Point Reset
Value
20
40
60
80
OA Temperature (°F)
An example of discharge temperature reset based on outdoor
air temperature is illustrated in Figure 15 (Heating Reset
Type Flag is set to “OAT” in this example). When the current
outdoor air temperature is greater than or equal to the
Minimum Heating Setpoint Reset Value (60°F in this
example), the Effective Discharge Heating Setpoint is set
equal to the Minimum Discharge Heating Setpoint (60°F in
this example). This is shown as Point C in Figure 15. When
the current outdoor air temperature is less than or equal to
the Maximum Heating Setpoint Reset Value (20°F in this
example), the Effective Discharge Heating Setpoint is set
equal to the Maximum Discharge Heating Setpoint (120°F in
this example). This is shown as Point A in Figure 15. When
the current outdoor air temperature is between the Minimum
Heating Setpoint Reset Value and the Maximum Heating
Setpoint Reset Value, the Effective Discharge Heating
Setpoint increases linearly between the Minimum Discharge
Heating Setpoint and Maximum Discharge Heating Setpoint.
This is shown as Point B in Figure 15.
Note: The Minimum Heating Setpoint Reset Value and
Maximum Heating Setpoint Reset Value are displayed
on the keypad/display without engineering units. The
values represent temperature (°F or °C) when the
Heating Reset Type Flag is set to “Space,” “Return” or
“OAT.” The values represent percentage (%) when the
Heating Reset Type Flag is set to “Ext mA” or “Ext V.”
External Discharge Temperature Reset
The Effective Discharge Heating Setpoint can be reset based
on a field supplied analog voltage or current signal. This
signal can be in the range of 0-10 VDC or 0-20 mA. When
the Heating Reset Type Flag is set to “Ext V” or “Ext mA,”
the Effective Discharge Heating Setpoint varies linearly
between the Minimum Discharge Heating Setpoint and the
Maximum Discharge Heating Setpoint as the field voltage or
current signal varies between a minimum and maximum (or
maximum and minimum) value.
80
The range and type of field reset signal is configured using
the Minimum Heating Setpoint Reset Value and the
Maximum Heating Setpoint Reset Value and setting a
jumper on the main control board associated with analog
input MCB-AI02. The analog input jumper is placed in
either the “voltage” or “current” position. When the jumper
is in the “voltage” position, the range of the input signal can
be from 0-10 VDC and when in the “current” position, 0-20
mA. The input range is scaled using the Minimum Heating
Setpoint Reset Value and the Maximum Heating Setpoint
Reset Value parameters. If for example, the field signal is to
be 1-5 VDC, the Minimum Heating Setpoint Reset Value
must be set to 10 (10%) since 1 VDC is 10% of the 0-10
VDC range. The Maximum Heating Setpoint Reset Value
must be set to 50 (50%) since 5 VDC is 50% of the 0-10
VDC range.
Refer to “External Discharge Air Reset Signal” in the “Field
Wiring” section of IM 710, MicroTech II Vertical SelfContained Systems Unit Controller.
Reset based on an external signal can be “direct acting”
where the Effective Discharge Heating Setpoint increases as
the field signal increases or it can be “reverse acting” where
the Effective Discharge Heating Setpoint decreases as the
field signal increases. The following are examples of both
“direct acting” and “reverse acting” reset.
An example of “direct acting” discharge temperature reset
based on an external 1-5 VDC signal is illustrated in
Figure 16 on page 81. When the external voltage signal is
less than or equal to the Minimum Heating Setpoint Reset
Value (1 VDC in this example), the Effective Discharge
Heating Setpoint is set equal to the Minimum Discharge
Heating Setpoint (60°F in this example). This is shown as
Point A in Figure 16 on page 81. When the external voltage
signal is greater than or equal to the Maximum Heating
Setpoint Reset Value (5 VDC in this example), the Effective
Discharge Heating Setpoint is set equal to the Maximum
McQuay OM-711-1
Effective Discharge Heating Set Point
Figure 16: Direct Acting External Reset
C
90°F
Minimum
Discharge
Heating Set
Point = 60°F
B
Maximum
Discharge
Heating Set
Point = 120°F
A
Figure 17: Reverse acting external reset
Effective Discharge Heating Set Point
Discharge Heating Setpoint (120°F in this example). This is
shown as Point C in Figure 16. When the external voltage
signal is between the Minimum Heating Setpoint Reset
Value and the Maximum Heating Setpoint Reset Value, the
Effective Discharge Heating Setpoint increases linearly
between the Minimum Discharge Heating Setpoint and
Maximum Discharge Heating Setpoint. This is shown as
Point B in Figure 16.
Maximum
Discharge
Heating Set
Point = 120°F
A
B
90°F
Minimum
Discharge
Heating Set
Point = 60°F
C
Maximum Heating
Set Point Reset
Value (10%)
Minimum Heating
Set Point Reset
Value (50%)
5
1
3
External Signal (Vdc)
Network Discharge Temperature Reset
Minimum Heating
Set Point Reset
Value (10%)
Maximum Heating
Set Point Reset
Value (50%)
5
1
3
External Signal (Vdc)
When the Heating Reset Type Flag is set to “None,” the
Effective Discharge Heating Setpoint is set equal to the
Discharge Heating Setpoint. The Discharge Heating Setpoint
can then be set via a network signal to meet the discharge air
temperature requirements.
Discharge Fan Capacity Control
An example of “reverse acting” discharge temperature reset
based on an external 1-5 VDC signal is illustrated in
Figure 17. When the external voltage signal is less than or
equal to the Maximum Heating Setpoint Reset Value (10%
or 1 VDC in this example), the Effective Discharge Heating
Setpoint is set equal to the Maximum Discharge Heating
Setpoint (120°F in this example). This is shown as Point A
Figure 17. When the external voltage signal is greater than or
equal to the Minimum Heating Setpoint Reset Value (50% or
5 VDC in this example), the Effective Discharge Heating
Setpoint is set equal to the Minimum Discharge Heating
Setpoint (60°F in this example). This is shown as Point C in
Figure 17. When the external voltage signal is between the
Maximum Heating Setpoint Reset Value and the Minimum
Heating Setpoint Reset Value, the Effective Discharge
Heating Setpoint decreases linearly between the Maximum
Discharge Heating Setpoint and Minimum Discharge
Heating Setpoint. This is shown as Point B in Figure 17.
Note: The Minimum Heating Setpoint Reset Value and
Maximum Heating Setpoint Reset Value are
displayed on the keypad/display without engineering
units. The values represent temperature (°F or °C)
when the Heating Reset Type Flag is set to “Space,”
“Return” or “OAT.” The values represent percentage
(%) when the Heating Reset Type Flag is set to “Ext
mA,” “Ext V” or “Airflow.”
McQuay OM-711-1
When a unit is equipped with discharge fan inlet guide vanes
or a discharge fan AFD, there are three optional methods for
controlling the discharge fan airflow. These are duct static
pressure control direct building static pressure control and
position control. The following sections describe the two
methods.
Duct Static Pressure Control
When the Discharge Fan Capacity Control Flag is set to
“DuctPres,” the controller modulates the discharge fan
capacity as required to maintain the Duct Static Pressure
Setpoint. To do this it uses three PID control loop parameters
to modulate the discharge inlet vane position or AFD speed
as the duct static pressure changes. These are Duct Static
Pressure Proportional Band, Duct Static Pressure Integral
Time, and Duct Static Pressure Period. Although these
parameters can be adjusted, for most applications, the
factory default values provide the best control. For detailed
information regarding tuning PID control loop parameters,
refer to “MicroTech II DDC Features” on page 90.
Duct static pressure control of the discharge air fan airflow is
overridden under three conditions:
1. The first condition is at unit startup. The discharge
airflow is held at minimum speed (17% for inlet vanes,
0% for AFDs) for the first thirty seconds of the Recirc
operating state.
2. The second condition is when “post heat” operation is
active. Refer to “Post Heat Operation” on page 83.
81
3. The third condition is when the discharge inlet vanes
modulate down to 17% or the AFD speed is reduced to
25%. The controller does not allow the capacity to
modulate below these fixed values.
Table 48: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Duct Pressure
Duct Static P Setup
Unit Configuration
Parameter Name
commanded setting and then can be adjusted via the unit
keypad/display. The Remote Discharge Fan Capacity
Setpoint can be adjusted from the fixed minimum (17% for
vanes or 25% for AFD applications) to 100%. When the
Discharge Fan Capacity Control Flag is set to “DuctPres,”
the Remote Discharge Fan Capacity Setpoint has no effect
on the unit operation.
DuctSP Spt= 1.00
“WC
Duct Static Pressure
Setpoint
Direct Building Static Pressure Control
DSP Db= 0.080 “WC
Duct Static Pressure
Deadband
Table 50: Programmable parameters
DSP Propbd= 6.0
“WC
Duct Static Pressure
Proportional Band
DSP IntTime= 12.0
sec
Duct Static Pressure
Integral Time
DSP Period= 10.0
sec
Duct Static Pressure
Period
2nd P Sensor= None
Second Pressure
Sensor Present Flag
DF CapCtrl=
DuctPres
Discharge Fan
Capacity Control Flag
Keypad/Display ID
Menu Name
Item Name
BldgSP Spt= 0.05 “WC
Building Static Pressure
Setpoint
BSP Db= 0.010 “WC
Building Static Pressure
Deadband
BSP Propbd= 1.0 “WC
Building Static Pressure
Proportional Band
BSP IntTime= 10.0 sec
Building Static Pressure
Integral Time
BSP Period= 5.0 sec
Building Static Pressure
Period
2nd P Sensor= None
Second Pressure
Sensor Present Flag
Bldg Pressure
Building Static
P Setup
Two Duct Static Pressure Sensors
Parameter Name
When a unit is equipped with discharge fan inlet guide vanes
or a discharge fan AFD, a second duct static pressure sensor
is optional. If a second duct static pressure sensor (SPS2) is
connected, the Second Pressure Sensor Present Flag can be
set to “Duct.” The controller then automatically selects the
lower of the two sensed pressures and uses this value to
control discharge fan airflow (the Duct Press= parameter
indicates the lower of the two readings). On larger buildings,
this strategy can be used to assure that adequate static
pressure is available throughout the VAV system.
When a unit is equipped with supply fan inlet guide vanes or
AFDs they can be controlled based on building static
pressure. When the Discharge Fan Capacity Control Flag is
set to “BldgPres” and the Second Pressure Sensor Present
Flag is set to “Bldg,” the controller modulates the supply fan
capacity to maintain the Bldg Static Pressure Setpoint.
Note: If a second duct sensor is not installed, the Second
Note: Note that this feature requires an optional building
Pressure Sensor Present Flag must be set to “None.”
Discharge Fan Direct Position Control
Table 49: Programmable parameters
Keypad/Display ID
Menu Name
Unit
Configuration
Item Name
Parameter Name
DF CapCtrl= DuctPres
Discharge Fan
Capacity Control Flag
Remote DF Cap=
25%
Remote Discharge Fan
Capacity Setpoint
When a unit is equipped with discharge fan inlet guide vanes
or a discharge fan AFD, the inlet guide vane position or AFD
speed can be controlled to a specific position setpoint based
on a network signal. When the Discharge Fan Capacity
Control Flag is set to “Position,” the controller positions the
discharge fan inlet vanes or AFD speed to the Remote
Discharge Fan Capacity Setpoint. Normal duct static
pressure control is overridden in this case. If network
communications is interrupted or is not present, the Remote
Discharge Fan Capacity Setpoint remains at the last
82
Unit
Configuration
static pressure sensor.
To do this it uses three PID control loop parameters to
modulate the discharge capacity as the building static
pressure changes. These are Building Static Pressure
Proportional Band, Building Static Pressure Integral Time
and Building Static Pressure Period. Although these
parameters can be adjusted, for most applications, the
factory default values for these parameters provide the best
control. For detailed information regarding tuning PID
control loop parameters; refer to “MicroTech II DDC
Features” on page 90.
Building static pressure control of the supply air fan airflow
is overridden.
1. When the supply fan capacity modulate down to 17% or
the AFD speed is reduced to 25%. The controller does
not allow the supply fan capacity to modulate below
these fixed values.
McQuay OM-711-1
Post Heat Operation
“No” or the Unoccupied Heating Setpoint is set to 0°F. The
following is a description of unoccupied heating operation:
Table 51: Programmable parameters
If the space temperature falls to the Unoccupied Heating
Setpoint while the unit is in the Off Unoc operating state, the
unit starts and runs. The controller enters the UnocHtg
operating state after the normal startup sequence. See
“Startup Control” on page 61. The UnocHtg operating state
is similar to the Heating operating state except that the
outdoor air dampers remain closed in the UnocHtg operating
state.
Keypad/Display ID
Menu Name
Item Name
Timer Settings
Post Heat= 0 min
Parameter Name
Post Heat Timer
After leaving the Recirc or Heating operating state and
entering either the Fan Only or Min DAT operating state, the
unit performs “post heat” operation if the Post Heat Timer is
set to a non zero value. “Post heat” operation occurs within
the Fan Only or MinDAT operating state. During “post heat”
operation, the VAV Box Output (MCB-B012) remains open
(heat) while the discharge fan capacity is forced to a
minimum value (17% position for inlet vanes, 25% speed for
AFD). By forcing the discharge fan capacity to a minimum
value before the VAV Box Output (MCB-B012) closes
(cool), “post heat” operation is designed to prevent duct
over-pressurization by decreasing the duct pressure before
the VAV boxes can close. For detailed information regarding
the VAV Box Output, refer to the “Field Wiring” section of
IM710, MicroTech II Vertical Self-Contained Systems Unit
Controller.
“Post heat” operation remains active until either the
discharge fan capacity reaches the minimum value or until
the Post Heat Timer expires, whichever occurs first. When
“post heat” operation ends, normal duct static pressure or
position control resumes.
Note: During “post heat” operation and for 120 seconds
afterward, the proof of airflow input is ignored. This
is to prevent nuisance Fan Fail fault alarms that may
occur if the airflow switch opens during or following
“post heat” operation. The unit cannot leave the Fan
Only or Min DAT operating state while the airflow
switch input is being ignored.
When the space temperature rises above the Unoccupied
Heating Setpoint by more than the Unoccupied Heating
Differential, heating operation ends and the controller shuts
down the fans and returns to the Off Unoc state.
Note: The Unoccupied Heating Setpoint cannot be set
higher than the Occ Htg Spt= parameter.
Emergency Space Sensor Failure Operation
The unit starts and runs in an emergency mode of operation
if all of the following are true:
1. The Space Sensor Present Flag is set to “Yes”
2. The Unoccupied Heating Setpoint is set higher than 0°F
3. The current value of the OA Temp= parameter is below
40°F.
4. The Space Temp problem alarm occurs.
5. Unit is equipped with a functioning return temperature
sensor.
In this mode of operation the unit starts and runs
continuously using the return air temperature sensor as the
“Control Temperature.” See “Control Temperature” on page
62.
Unoccupied Cooling (Night Setup)
Table 53: Programmable parameters
Keypad/Display ID
Unoccupied Control
Menu Name
Unoccupied Heating (Night Setback)
Item Name
UnoccClg Spt= 85.0 ºF
Unoccupied Cooling
Setpoint
UnoccClgDiff= 3°F
Unoccupied Cooling
Differential
Space Sensor= Yes
Space Sensor
Present Flag
Zone Cooling
Table 52: Programmable parameters
Keypad/Display ID
Menu Name
Item Name
Zone
Heating
Parameter Name
UnoccHtg Spt= 55.0 ºF
Unoccupied Heating
Setpoint
UnoccHtgDiff= 3°F
Unoccupied Heating
Differential
Space Sensor= Yes
Space Sensor Present
Flag
Unit
Configuration
If an optional space (or zone) temperature sensor (ZNT1) is
connected to the controller, the Space Sensor Present Flag is
set to “Yes” and the Unoccupied Heating Setpoint is set
higher than 0°F, unoccupied heating (night setback)
operation is available. Unoccupied heating operation is
disabled if either the Space Sensor Present Flag is set to
McQuay OM-711-1
Unit
Configuration
Parameter Name
If an optional space (or zone) temperature sensor (ZNT1) is
connected to the controller, the Space Sensor Present Flag is
set to “Yes” and the Unoccupied Cooling Setpoint is set
lower than 99°F, unoccupied cooling (night setup) operation
is available. Unoccupied cooling operation is disabled if
either the Space Sensor Present Flag is set to “No” or the
Unoccupied Cooling Setpoint is set to 99°F. Below is a
description of unoccupied cooling operation:
If the space temperature rises to the Unoccupied Cooling
Setpoint while the unit is in the Off Unoc state, the unit starts
and runs.1 If the unit has an economizer and conditions are
83
acceptable for economizer cooling, the controller enters the
UnocEcon operating state after the normal startup sequence.
If conditions are not acceptable for economizer cooling (or
the unit has no economizer), the controller enters the
UnocClg operating state and activates mechanical cooling
after the normal startup sequence. The UnocEcon and
UnocClg operating states are similar to the Econo and
Cooling operating states except that the Eff MinOA Pos=
parameter is set to 0%.
When the space temperature drops below the Unoccupied
Cooling Setpoint by more than the Unoccupied Cooling
Differential, cooling operation ends and the controller shuts
down the fans and returns to the Off Unoc state.
Note: The Unoccupied Cooling Setpoint cannot be set
lower than the Occ Clg Spt= parameter.
Purge
Table 54: Programmable parameters
Keypad/Display ID
Menu Name
Zone
Cooling
OA Damper
The unit returns to the Off Unoc state when any of the
following three conditions occur:
1. The Space Temp= parameter value is less than the
Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband.
2. The OA Ambient= parameter in the OA Damper menu
indicates “High.”
3. The outdoor air temperature rises above the space
temperature by more than 2°F.
As conditions allow, purge control cycles the unit in this
manner until normal occupied operation begins. If the
scheduled occupied startup time occurs during purge
operation, the unit continues running without interruption.
Parameter Name
Alarm Control
Eff Clg Spt= 75.0 ºF
Effective Cooling
Enable Setpoint
The following are descriptions of the various alarms that can
occur in discharge air control (DAC) self-contained units.
Clg Deadband= 1.0 ºF
Cooling Enable
Deadband
Max Purge= 60 min
Maximum Purge Time
Item Name
If a unit is equipped with an airside economizer and an
optional space (or zone) temperature sensor (ZNT1) is
connected to the controller, pre-occupancy purge control is
available. Designed to take advantage of cool pre-dawn
outdoor air, purge control starts the fans and modulates the
economizer dampers to maintain occupied cooling
requirements during unoccupied periods. The purge function
can only be used in conjunction with the unit internal time
schedule or with a network supplied time schedule.
Purge operation is possible only during a time window prior
to occupancy that is defined by the Maximum Purge Time
parameter (0 to 240 minutes). For example, if the unit is
scheduled to start at 6:30 a.m., a Maximum Purge Time of 60
minutes (default) allows purge operation to occur between
5:30 a.m. and 6:30 a.m.
During the purge time window, the unit starts and runs when
the following three requirements are all met:
1. The Space Temp= parameter value is greater than the
Effective Cooling Enable Setpoint by more than half the
Cooling Enable Deadband.
2. The OA Ambient= parameter in the OA Damper menu
indicates “Low.”
3. The OA Temp= parameter value is below the Space
Temp= parameter value by more than 4°F.
1. The unit does not activate unoccupied heating or cooling
operation if the UnitStatus= parameter in the System menu
indicates “Off Man,” “Off Sw,” “Off Net” or “Off Alm.”
84
During purge operation, the controller enters and remains in
the UnocEcon operating state after the normal startup
sequence. Mechanical cooling is disabled. Economizer
control during purge operation is similar to that during
occupied operation.
CAUTION
Ivestigate and eliminate the cause of a manual reset alarm
before placing the unit or any disabled equipment in it back
into service. Failure to do so can cause erratic operation or
equipment damage.
Faults
Freeze
When a unit is equipped with a Waterside Economizer
chilled water, hot water, or steam coil, the Freeze fault
occurs when the optional freezestat (FS1) contacts open
(binary input MCB-BI7 off) as a result of detecting an
abnormally low water or steam coil temperature while the
fans are running.
When the Freeze fault occurs, the controller shuts down the
fans, closes the outdoor air dampers, opens the Waterside
Economizer or chilled water and heating valves and sets a
10-minute timer.
When the 10-minute timer expires, the controller checks the
freezestat input again. If the freezestat contacts are closed
(binary input MCB-BI7 on), the valves close. If the
freezestat contacts are still open (binary input MCB-BI7 off),
the valves remain open, and the 10-minute timer resets. This
continues until the fault is manually cleared through the unit
keypad or via a network signal.
Smoke
The Smoke fault occurs when the contacts of the field smoke
detector open (binary input MCB-BI8 off).
When the Smoke fault occurs, the unit immediately shuts
down. The unit remains shut down until the smoke detector
McQuay OM-711-1
is manually reset and the Smoke fault is manually cleared
through the unit keypad or via a network signal.
MAT Sensor
If the mixed air temperature sensor (MAT) fails (analog
input MCB-AI6 open or short-circuited) while it is acting as
the “Control Temperature” (CtrlTemp Src= parameter is set
to “MAT”), the MAT Sensor fault occurs.
When the MAT Sensor fault occurs, the unit shuts down. It
remains shut down until the MAT Sensor fault is manually
cleared through the unit keypad or via a network signal.
OAT Sensor
If the outdoor air temperature sensor (OAT) fails (analog
input MCB-AI5 open or short-circuited) while it is acting as
the “Control Temperature” (CtrlTemp Src= parameter is set
to “OAT”), the OAT Sensor fault occurs.
When the OAT Sensor fault occurs, the unit shuts down. It
remains shut down until the OAT Sensor fault is manually
cleared through the unit keypad or via a network signal.
Space Sensor
When the Duct Hi Limit fault occurs, the unit shuts down.
The unit remains shut down until the Duct Hi Limit fault is
manually cleared through the unit keypad or via a network
signal.
Hi Return Tmp
If the unit is equipped with a return air temperature sensor
and the Return Air= parameter value exceeds the Hi Return
Alm= value in the Alarm Limits menu, while the unit is
operational, the Hi Return Tmp fault occurs.
When the Hi Return Tmp fault occurs, the unit is shut down.
It remains shut down until the Hi Return Tmp fault is
manually cleared through the unit keypad or via a network
signal.
Hi Disch Tmp
If the Disch Air= parameter value exceeds the Hi Disch
Alm= setting in the Alarm Limits menu, while the unit is
operational, the Hi Disch Tmp fault occurs.
When the Hi Disch Tmp fault occurs, the unit shuts down. It
remains shut down until the Hi Disch Tmp fault is manually
cleared through the unit keypad or via a network signal.
If the optional space temperature sensor (ZNT1) fails
(analog input MCB-AI1 open or short-circuited) while it is
acting as the “Control Temperature” (CtrlTemp Src=
parameter is set to “Space”) and the unit has no return air
sensor, the Space Sensor fault occurs.
Lo Disch Tmp
When the Space Sensor fault occurs, the unit shuts down. It
remains shut down until the Space Sensor fault is manually
cleared through the unit keypad or via a network signal.
When the Lo Disch Tmp fault occurs, the unit shuts down. It
remains shut down until the Lo Disch Tmp fault is manually
cleared through the unit keypad or via a network signal.
Return Sensor
If the unit is equipped with a return air temperature sensor
(RAT) and it fails (analog input MCB-AI4 open or shortcircuited) while it is acting as the “Control Temperature”
(CtrlTemp Src= parameter is set to “Return”), the Return
Sensor fault occurs.
If the Disch Air= parameter value drops below the Lo Disch
Alm= setting in the Alarm Limits menu while the unit is
operational, the Lo Disch Tmp fault occurs.
Note: The Lo Disch Tmp fault is ignored when the unit
leaves the Startup operating state for a time period
defined by the Low DAT= parameter in the Timer
Settings menu and when the unit is in the Cooling
operating state.
Fan Fail
Disch Sensor
If differential pressure switch PC7 fails to detect airflow
(binary input MCB-BI6 off) after the unit leaves the Startup
operating state or any time afterward, while the unit is
running, and the static pressure is less than half the setpoint
the Fan Fail fault occurs.
If the discharge air temperature sensor (DAT) fails (analog
input MCB-AI3 open or short-circuited), the Disch Sensor
fault occurs.
When the Fan Fail fault occurs, the unit shuts down. It
remains shut down until the Fan Fail fault is manually
cleared through the unit keypad or via a network signal.
When the Disch Sensor fault occurs, the unit shuts down. It
remains shut down until the Disch Sensor fault is manually
cleared through the unit keypad or via a network signal.
Exceptions:
When the Return Sensor fault occurs, the unit shuts down. It
remains shut down until the Return Sensor fault is manually
cleared through the unit keypad or via a network signal.
Duct Hi Limit
If the unit is equipped with discharge fan inlet vanes or a
AFD and the contacts of the duct high pressure limit control
(DHL) open (binary input MCB-BI14 off), the Duct Hi
Limit fault occurs.
McQuay OM-711-1
1. If the unit is equipped with discharge fan inlet vanes or a
discharge fan AFD and “post heat” operation is active,
the Fan Fail fault is ignored during “post heat” and for
two minutes following “post heat” operation. While the
Fan Fail fault is being ignored, the unit does not leave
the Fan Only or Min DAT operating state. For detailed
information regarding “post heat” operation, refer to
“Post Heat Operation” on page 83.
85
2. On units equipped with a discharge fan AFD, the Fan
Fail fault only occurs if the Fan Retry problem
described below has first occurred twice within the
previous twenty-four hour period. The conditions that
cause the Fan Retry problem and the action taken are the
same as for the Fan Fail fault. The difference being that
the Fan Retry alarm is an automatically clearing alarm
once the unit is shut off. This allows the unit to attempt
to restart up to three times within a twenty-four hour
period.
Note: The three retry counter is reset anytime the unit is
disabled by any of the following methods:
1.
2.
3.
4.
Fault alarm
External enable/disable switch input
Ctrl Mode= parameter in the System menu set to “Off”
Emerg Override= parameter in the Occupancy menu set
to “Off.”
5. Appl Mode= parameter in the System menu set to “Off”
via a network signal.
OA Dmpr Stuck
On units equipped with a 100% outdoor air control, the
outdoor air dampers are driven fully open during the Startup
operating state before the discharge fan is started. If the OA
Damper Pos= parameter in the OA Damper menu does not
indicate 50% or greater when the unit leaves the Startup
operating state, the OA Dmpr Stuck fault occurs.
When the OA Dmpr Stuck fault occurs, the unit is shut
down. The unit remains shut down until the OA Dmpr Stuck
fault is manually cleared through the unit keypad or via a
network signal.
Problems
Freeze
When a unit is equipped with a Waterside Economizer Coil
chilled water, hot water, or steam coil, the Freeze problem
occurs when the optional freezestat (FSl) contacts open
(binary input MCB-B7 off) as a result of detecting an
abnormally low air temperature while the fans are off.
When the Freeze problem occurs, the controller opens the
Waterside Economizer or chilled water and heating valves
and sets a 10-minute timer.
When the 10-minute timer expires, the controller checks the
freezestat input again. If the freezestat contacts are closed
(binary input MCB-BI7 on), the valves close. If the
freezestat contacts are still open (binary input MCB-BI7 off),
the valves remain open, and the 10-minute timer resets. This
continues while the unit remains off.
Whenever the freezestat closes (binary input MCB-BI7 on),
the Freeze problem automatically clears. This feature
protects the coil(s) and allows the system to start normally
when an occupied command is received.
MAT Sensor
86
If the mixed air temperature sensor (MAT) fails (analog
input MCB-AI6 open or short-circuited), the MAT Sensor
problem occurs, disabling the waterside economizer.
When the alarm condition is no longer present, the MAT
Sensor problem automatically clears.
EWT Sensor
If the entering water temperature sensor (EWT) fails (analog
input MCB-AI7 open or short-circuited), the EWT Sensor
problem occurs. When the EWT Sensor problem occurs,
waterside economizer cooling is disabled.
When the alarm condition is no longer present, the EWT
Sensor problem automatically clears.
OAT Sensor
If the outdoor air temperature sensor (OAT) fails (analog
input MCB-AI5 open or short-circuited) and it is not acting
as the “Control Temperature” (CtrlTemp Src= parameter is
not set to “OAT”), the OAT Sensor problem occurs.
When the OAT Sensor problem occurs, the unit continues to
operate with the following modifications:
1. Discharge temperature setpoint reset based on outdoor
air is unavailable.
2. High ambient heating lockout is disabled.
When the alarm condition is no longer present, the OAT
Sensor problem automatically clears.
Space Sensor
If the optional space temperature sensor ZNT1 fails (analog
input MCB-AI1 open or short-circuited) on a unit equipped
with a return air temperature sensor, the Space Sensor
problem occurs as long as the Space Sensor= parameter in
the Unit Configuration menu is set to “Yes.” If this
parameter is set to “No” the Space Sensor problem
indication is disabled.
When the Space Sensor problem occurs, the unit continues
to operate with the following modifications:
1. Discharge temperature setpoint reset based on space
temperature is unavailable.
2. If the space temperature input is acting as the “Control
Temperature” (CtrlTemp Src= parameter is set to
“Space”), the controller automatically changes the
CtrlTemp Src= parameter to “Return.”
When the Space Sensor problem occurs during an
unoccupied time period, the unit starts and runs continuously
in the UnocHtg operating state, using the return air
temperature sensor as the “Control Temperature” if all of the
following conditions are true:
1. The unit is equipped with a return air temperature sensor.
2. The OA Temp= parameter value is below 40 °F.
3. The UnoccHtg Spt= parameter in the Zone Heating
menu is set higher than 0°F.
McQuay OM-711-1
When the alarm condition is no longer present, the Space
Sensor problem automatically clears and normal unit
operation resumes.
Return Sensor
If the return air temperature sensor (RAT) fails (analog input
MCB-AI4 open or short-circuited) while it is not acting as
the “Control Temperature” (CtrlTemp Src= parameter is not
set to “Return”), the Return Sensor problem occurs.
When the Return Sensor problem occurs, the unit continues
to operate with the following modifications:
1. Discharge temperature setpoint reset based on return
temperature is unavailable.
2. The Hi Return Tmp fault is disabled.
When the alarm condition is no longer present, the Return
Sensor problem automatically clears.
Low Airflow
The Low Airflow problem is a safety feature designed to
protect units equipped with electric heat. If the discharge air
temperature is greater than the mixed air temperature by
60°F or the discharge air temperature is greater than 145°F,
heating is disabled. Heating remains disabled until the Low
Airflow problem is manually cleared through the keypad or
via a network signal.
Heat Fail
The Heat Fail is applicable only to units equipped with
electric heat. When the Heat Fail input is in the alarm
position, the unit continues to operate, but one or two stages
of the electric heat is disabled through a high limit contactor.
When the alarm condition is no longer present, the Heat Fail
problem automatically clears.
Fan Retry
When a unit is equipped with a discharge fan AFD and if the
differential pressure switch PC7 fails to detect airflow
(binary input MCB-BI6 off) within two minutes after leaving
the Startup operating state or any time afterward while the
unit is running, the Fan Retry problem occurs.
When the Fan Retry problem occurs, the unit is shut down.
Once the unit is shut down the Fan Retry problem is
automatically cleared and the unit is free to restart.
Exceptions:
1. If “post heat” operation is active, the Fan Retry problem
is ignored during “post heat” and for two minutes
following “post heat” operation. While the Fan Retry
problem is being ignored, the unit does not leave the Fan
Only or Min DAT operating state. For detailed
information regarding “post heat” operation, refer to
“Post Heat Operation” on page 83.
2. The Fan Retry problem only will occur twice within a
twenty-four hour period. If the conditions that cause the
Fan Retry problem occur a third time within this period,
the Fan Fail fault described above occurs instead. The
McQuay OM-711-1
action taken as a result of the Fan Fail fault is the same
as that for the Fan Retry alarm, the difference being that
the Fan Retry alarm is an automatically clearing alarm
once the unit is shut off while the Fan Fail fault requires
a manual clearing. This allows a unit equipped with a
discharge fan AFD to attempt to restart up to three times
within a twenty-four hour period.
Note: The three retry counter is reset anytime the unit is
disabled by the fault alarm.
Circ 1 (2, 3, 4, 5, or 6) High P
A High-pressure alarm occurs when the high-pressure switch
opens.
When the High-pressure fault occurs, the compressor shuts
down. It remains shut down until the High-pressure problem
is manually cleared through the unit keypad or via a network
signal.
Circ 1 (2, 3, 4, 5, or 6) Lo P/Frost
A Low-pressure or Frost alarm occurs when either the
low-pressure switch or frost switch opens.
When the alarm condition is no longer present, the
Low-pressure/Frost problem automatically clears.
When the alarm condition is no longer present, the
Lo P/Frost problem automatically clears. If the alarm occurs
three times between 2:00 am of one day and 2:00 am of the
next day, manually clear the alarm.
No Water Flow
On units equipped with a water flow switch, a No Water
Flow alarm occurs when an open water flow switch or a
network signal indicates a lack of water flow when water
flow should be present. Cooling provided by the
compressors or waterside economizer is disabled. An airside
economizer, if available, provides the only cooling.
When the alarm condition is no longer present, the No Water
Flow problem automatically clears.
Compr 1 (2, 3, 4, 5, or 6) MP Alm
A Motor protection alarm occurs when the compressors
motor protection switch opens.
When the alarm condition is no longer present, the Motor
protection problem automatically clears. If the alarm occurs
three times between 2:00 am of one day and 2:00 am of the
next day, manually clear the alarm.
Water Regulating Valve
On units equipped with Water Regulating Control. A Water
Reg Vlv alarm occurs when the greater of the two refrigerant
pressure readings is below the Head Pressure Setpoint= by
more than the deadband for more than five minutes. At least
one compressor has to be on and the entering water
temperature needs to be less than 58°F. When the Water Reg
Vlv problem occurs, Mechanical Cooling is disabled and
87
remains disabled until the Water Reg Vlv problem is
manually cleared through the keypad or via a network signal.
of RS-485 communication between the two boards, the
CompB1 Comm Fail problem occurs.
CompB1 Clg Ena
If the MCB is not communicating with either cooling control
board (CCB1 or CCB2), the unit is not allowed to enter the
Cooling operating state.
When a unit is equipped with compressorized cooling, the
main control board (MCB) controls the cooling outputs on
and receives cooling circuit input information from the
compressor control board (CCB1) via an RS-485 bus
interface between the two boards. If the MCB detects a loss
of RS-485 communication between the two boards there
must be an external method for the MCB to command the
CCB1 board to shut off the cooling. This is accomplished
with a “cooling enable” output from MCB (MCB-BO11)
hard wired to a “cooling enable” input to the CCB1 board
(binary input CCB1-AI5 via a 1 k ohm resistor).
If the MCB is communicating with the CCB1 board and the
“cooling enable” output from MCB is on but the “cooling
enable” input to CCB1 remains off, indicating a wiring
problem between the boards, the CompB1 Clg Ena problem
occurs.
When the CompB1 Clg Ena problem occurs, all Compressors
are disabled. Cooling remains disabled until the problem is
corrected and the CompB1 Clg Ena problem is manually
cleared through the unit keypad or via a network signal.
CompB2 Clg Ena
When a unit is equipped with compressorized cooling, the
main control board (MCB) controls the cooling outputs on
and receives cooling circuit input information from the
second compressor control board (CCB2) via an RS-485 bus
interface between the two boards. If the MCB detects a loss
of RS-485 communication between the two boards there
must be an external method for the MCB to command the
CCB2 board to shut off the cooling on that circuit. This is
accomplished with a “cooling enable” output from MCB
(MCB-BO11) hard wired to a “cooling enable” input to the
CCB2 board (binary input CCB2-AI5 via a 1 k ohm
resistor).
If the MCB is communicating with the CCB2 board and the
“cooling enable” output from MCB is on but the “cooling
enable” input to CCB2 remains off, indicating a wiring
problem between the boards, the CompB2 Clg Ena problem
occurs.
When the CompB2 Clg Ena problem occurs, Compressors
#5 and #6 are disabled. Cooling remains disabled until the
problem is corrected and the CompB2 Clg Ena problem is
manually cleared through the unit keypad or via a network
signal.
CompB1 Comm Fail
When a unit is equipped with compressorized cooling, the
main control board (MCB) controls the cooling outputs on
and receives cooling circuit input information from the
compressor control board (CCB1) via an RS-485 bus
interface between the two boards. If the MCB detects a loss
88
When the CompB1 Comm Fail problem occurs while the
unit is in the Cooling operating state, the unit remains in the
Cooling operating state. The current cooling capacity in the
MCB is set to 0%. Any cooling that may be operating at the
time of the communication failure remains on (on either
circuit) until the MCB leaves the Cooling operating state due
to normal operation. When the MCB leaves the Cooling
operating state the “cooling enable” output (MCB-BO11) is
turned off and, therefore, the “cooling enable” input to the
CCB1 and CCB2 boards is removed (analog inputs CCB1AI5 and CCB2-AI5 off) and this causes the CCB1 and CCB2
to completely stage off all cooling. The MCB then does not
re-enter the Cooling operating state until communication is
re-established CCB1. When communications between the
MCB and CCB1 is re-established, the CompB1 Comm Fail
problem automatically clears.
CompB2 Comm Fail
When a unit is equipped with compressorized cooling, the
main control board (MCB) controls the cooling outputs on
and receives cooling circuit input information from the
compressor control board (CCB2) via an RS-485 bus
interface between the two boards. If the MCB detects a loss
of RS-485 communication between the two boards, the
CompB2 Comm Fail problem occurs.
When the CompB2 Comm Fail problem occurs while the
unit is not in the Cooling operating state, the unit is allowed
to enter the Cooling operating state as long as the MCB is
communicating with the first cooling control board (CCB1).
In this case the cooling capacity is limited to that available
from (CCB1). If the MCB is not communicating with either
cooling control board (CCB1 or CCB2), the unit is not
allowed to enter the Cooling operating state.
When the CompB2 Comm Fail problem occurs while the
unit is in the Cooling operating state, the unit remains in the
Cooling operating state. However, the maximum cooling
capacity is limited to that of (CCB1) if the MCB is
communicating with it. If the MCB is not communicating
with either cooling control board (CCB1 or CCB2), the
current cooling capacity in the MCB is set to 0%. Any
cooling that may be operating at the time of the
communication failure remains on (on either circuit) until
the MCB leaves the Cooling operating state due to normal
operation. When the MCB leaves the Cooling operating state
the “cooling enable” output (MCB-BO7) is turned off and,
therefore, the “cooling enable” input to the CCB1 and CCB2
boards is removed (analog inputs CCB1-AI5 and CCB2-AI5
off) and this causes the CCB1 and CCB2 to completely stage
off all cooling. The MCB then does not re-enter the Cooling
operating state until communication is re-established with
McQuay OM-711-1
CCB1. When communications between the MCB and CCB2
is re-established, the CompB2 Comm Fail problem
automatically clears.
When the CompB1 H/W warning occurs, unit operation is
not affected. The CompB1 H/W warning must be manually
cleared through the unit keypad or via a network signal.
Warnings
CompB2 H/W
Econo Stuck
On units equipped with an economizer, the Economizer Stuck
alarm occurs if either of the following conditions exist:
1. The Economizer position is greater than 10% and the
unit has been off for more than three minutes.
2. The Economizer position is less than 95% and the unit
has been is Mechanical Cooling with conditions
acceptable for Economizer operation for more than the
cooling stage time.
Airflow Switch
If the unit has been in the Off operating state for at least
thirty minutes and the PC7 airflow switch input to the main
controller indicates airflow (binary input MCB-BI6 on), the
Airflow Switch warning occurs. This normally indicates a
problem with the PC7 airflow switch.
When the Airflow Switch warning occurs, unit operation is
not affected. When the alarm condition is corrected, the
Airflow Switch warning must be manually cleared through
the unit keypad or via a network signal.
When a unit is equipped with compressorized cooling, the
main control board (MCB) controls the cooling outputs on
and receives cooling circuit input information from the
compressor control board (CCB2) via an RS-485 bus
interface between the two boards. If the MCB detects a loss
of RS-485 communication between the two boards there
must be an external method for the MCB to command the
CCB2 board to shut off the cooling on that circuit. This is
accomplished with a “cooling enable” output from MCB
(MCB-BO11) hard wired to a “cooling enable” input to the
CCB2 board (analog input CCB2-AI5 via a 1k ohm resistor).
If the MCB is communicating with the CCB2 board and the
“cooling enable” output from MCB is off but the “cooling
enable” input to CCB2 remains on, indicating that the
“cooling enable” input to the CCB2 board is “stuck” on, the
CompB2 H/W warning occurs.
When the CompB2 H/W warning occurs, unit operation is
not affected. Manually clear the CompB2 H/W warning
through the unit keypad or via a network signal.
Dirty Filter
If the pressure drop across the filter section in the unit
exceeds the setting of the PC5 differential pressure switch
while the unit is operational, the dirty filter input is removed
from MCB (binary input MCB-BI9 off) and the Dirty Filter
warning occurs.
When the Dirty Filter warning occurs, unit operation is not
affected. The Dirty Filter warning must be manually cleared
through the unit keypad or via a network signal.
CompB1 H/W
When a unit is equipped with compressorized cooling, the
main control board (MCB) controls the cooling outputs on
and receives cooling circuit input information from the
circuit #1 compressor control board (CCB1) via an RS-485
bus interface between the two boards. If the MCB detects a
loss of RS-485 communication between the two boards there
must be an external method for the MCB to command the
CCB1 board to shut off the cooling on that circuit. This is
accomplished with a “cooling enable” output from MCB
(MCB-BO11) hard wired to a “cooling enable” input to the
CCB1 board (analog input CCB1-AI5 via a 1k ohm resistor).
If the MCB is communicating with the CCB1 board and the
“cooling enable” output from MCB is off but the “cooling
enable” input to CCB1 remains on, indicating that the
“cooling enable” input to the CCB1 board is “stuck” on, the
Ckt1 H/W warning occurs.
McQuay OM-711-1
89
MicroTech II DDC Features
The MicroTech II unit controller uses PID control algorithms
(referred to as “PID objects”) to control modulating output
devices in order to keep a controlled variable at or near the
desired setpoint. These devices are generally either floatingpoint actuators or adjustable frequency motor drives (AFD).
There is a pair of outputs defined for each modulating device
to be controlled. One output energizes to increase the
capacity and the other energizes to decrease the capacity of
the modulating device. There are two different PID controls
schemes used to control the modulating output devices.
These are the “Direct PID Method” and the “Cascaded PID
Method.” The “Direct PID Method” uses one Velocity PID
object to directly control the modulating device outputs. The
“Cascaded PID Method” uses one Position PID and one
Velocity PID object in a “cascaded” manner to control the
modulating device outputs.
Direct PID Method
In some cases, the controller uses a Velocity PID object
directly to turn actuator control outputs on and off to
maintain a controlled variable at a setpoint. In these cases the
setpoint and current value of the controlled variable are input
to the Velocity PID object. The Velocity PID object
determines a “time on” for either the increase or decrease
output as necessary to reduce the “error” between the
setpoint and the controlled variable. This information is
input into a position adjust output object (PAO), which in
turn commands the output device increase or decrease output
on and off, repositioning the actuator.
Note: In this method, position feedback from the control
actuators is not used for control purposes.
Table 55 on page 91 lists the modulating devices controlled
using this method. Figure 18 is a schematic representation of
this control scheme.
Cascaded PID Method
In some cases, the controller uses actuator position (or AFD
speed) feedback and a combination of a Position PID object
and a Velocity PID object to control actuator (or AFD)
control outputs to maintain a controlled variable at a
setpoint. In this “cascaded” control scheme, the setpoint and
the current value of the controlled variable are input to the
Position PID object. The Position PID object then calculates
a new actuator position (or AFD speed) setpoint and inputs
this into the Velocity PID object. The Velocity PID object
then compares the current actuator position (or AFD speed)
feedback signal to the new position setpoint and determines
a “time on” for either the increase or decrease output as
necessary to maintain the feedback signal at the current
position (or speed) setpoint. This information is input into a
position adjust output object (PAO), which in turn
commands the output device increase or decrease output on
and off, repositioning the actuator (or changing AFD speed).
Table 55 on page 91 lists the modulating devices controlled
using this method. Figure 19 is a schematic representation of
this control scheme.
Figure 18: Direct PID method control scheme
Set Point
+
Velocity PID
-
PAO
Actuator
Position
Controlled
Variable
Figure 19: Cascaded PID method control scheme
Set Point
+
-
Controlled
Variable
90
Position PID
+
Velocity PID
-
PAO
Actuator or
VFD Position
Actuator Position (or VFD Speed) Feedback
McQuay OM-711-1
Table 55: MicroTech II modulating output devices
Modulating Device
Decrease Binary Output
Increase Binary Output
PID Method
Controlled Variable
Hot Water Valve Actuator
MCB-BO9
MCB-BO10
Direct
Discharge Temperature
Steam Valve Actuator
MCB-BO9
MCB-BO10
Direct
Discharge Temperature
Chilled Water Valve Actuator
MCB-BO7
MCB-BO8
Direct
Discharge Temperature
Economizer Actuator
MCB-BO5
MCB-BO6
Cascaded
Discharge Temperature
Discharge Fan Inlet Vane
Actuator or AFD
MCB-BO13
MCB-BO14
Cascaded
Duct Static Pressure
Water Reg. Valve Actuator
MCB-BO7
MCB-BO8
Direct
Refrigerant Pressure
PID Control Parameters
Associated with each modulating output device, there is a set
of three adjustable PID control parameters. These are the
Period, Proportional Band and Integral Time.
Note: Since derivative control is not generally required in
HVAC control strategies, the Derivative Time
parameter of the PID object is set to 0 and is not
adjustable through the unit keypad/display. The
Derivative Time parameter can only be adjusted
using the MicroTech II Service Tool.
Since the factory settings for these parameters should
provide the best control action, field changes are not
recommended. If problems arise, first set these parameters
back to the factory settings if they have been changed in the
field. If adjustment is then required, use caution since
parameters grossly out of adjustment can cause erratic unit
operation and possible equipment damage. Make changes
only in small increments and to only one parameter at a time.
After each change, allow enough time for the system to
stabilize before further changes are made. Refer to the
following sections for guidelines regarding how the specific
parameters affect the control action of the PID algorithm.
Period
Unless grossly misadjusted, changing the Period parameter
generally has a relatively small effect on the PID control
action. It should generally be set to a value of the same
magnitude and within 1/4 to 2/3 the time constant of the
system being controlled. If the Period is set too long, loss of
system control will likely occur. If the Period is set too short,
dramatic system “hunting” will likely occur. When in doubt,
this parameter should be set to the factory default setting.
Note: The Period parameter is not allowed to be set higher
than the Integral Time parameter. If this is attempted
the Period parameter reverts to its previous setting.
Proportional Band and Integral Time
The Proportional Band and the Integral Time parameters
have a similar effect on the PID control action. Increasing
either the Proportional Band or the Integral Time has a
slowing effect on the control action. Decreasing either the
Proportional Band or the Integral Time has a speeding effect
McQuay OM-711-1
on the control action. Increasing or decreasing both
parameters at the same time has a more dramatic slowing or
speeding effect. Increasing one while decreasing the other
tends to have countering effects on the control action.
Therefore, if it becomes necessary to slow down or speed the
control action, these two parameter should generally not
both be changed at the same time. One parameter should
remain unchanged while the other is increased or decreased.
Proper “tuning” of the Proportional Band and the Integral
Time parameters involves finding an acceptable “balance”
between the two.
Note: The Integral Time parameter is not allowed to be set
lower than the Period parameter. If this is attempted
the Integral Time parameter reverts to its previous
setting.
Adjusting PID Control Parameters
Correcting System Instability (“Hunting”)
If the system control is unstable (“hunting”), this generally
means the control response is too “fast.” To correct system
“hunting,” generally the first step is to slow down the
response by increasing the Integral Time until the system
becomes stable. This may, however, cause “sluggishness” in
the controlled variable approach to the setpoint during
transient conditions (such as at unit start up).1 If system
“sluggishness” occurs after the Integral Time is adjusted, it
means the overall control response is now too “slow” and the
response must be speeded up by reducing the Proportional
Band. When the Proportional band is changed so that the
controlled variable approach to the setpoint is acceptable, it
may then be necessary to readjust the Integral Time to restabilize the control action.
When in doubt, these parameters should be set to the factory
default setting.
1. Once operating, check the system for sluggishness by
changing the setpoint and measuring the time it takes for the
controlled variable to reach the setpoint.
91
Correcting System “Sluggishness”
If the system control is “sluggish,” meaning the controlled
variable approach to the setpoint during transient conditions
(such as at unit start up) is too slow, this generally means the
overall control response is too “slow.”1 To correct system
“sluggishness,” the first step is to speed up the overall
system response by decreasing the Proportional Band so that
the controlled variable approach to the setpoint is acceptable.
This may, however, result in system instability (“hunting”).
If system instability occurs, the Integral Time should be
increased to slow down the control response and stabilize the
control action.
The PRAC function requires a “history,” and it may take
several excursions (perhaps as many as 10) above and below
setpoint for the new proportional band and integral setting to
be determined and for the control to settle out.
Note: After using the PRAC function, the new proportional
band and integral settings do not appear on the unit
keypad until power is subsequently cycled to the unit
controller.
When in doubt, these parameters should be set to the factory
default setting.
CAUTION
Misadjusting PID parameters can cause erratic
operation and equipment damage.
PID control parameters must be adjusted only by trained
personnel having a thorough understanding of how the
parameters affect overall system operation. Generally these
parameters do not need to be adjusted from the factory
default settings.
PRAC Tuning
Table 56: Programmable parameters
Keypad/Display ID
Parameter name
Menu name
Menu item
Duct Static P
Setup
PRAC= NO
Duct Static Pressure Control
PRAC Flag
Bldg Static P
Setup
PRAC= NO
Building Static Pressure Control
PRAC Flag
Chilled Water
Setup
PRAC= NO
Chilled Water Control PRAC Flag
Economizer Setup PRAC= NO
Economizer Control PRAC Flag
Heating setup
PRAC= NO
Heating Control PRAC Flag
Head Pressure
Setup
PRAC= NO
WRV Control PRAC Flag
In the event that PID parameters do need adjustment, an
automatic tuning function called PRAC (pattern recognition
adaptive control) is available for several of the Micro Tech II
control loops. Use these PRAC functions in lieu of manually
adjusting the various PID proportional band and integral
time control parameters.
Use the PRAC feature to tune the duct static pressure control
PID parameters, for example, change the Duct Static
Pressure Control PRAC Flag from No to Yes. Ten allow the
unit to control the duct static pressure in the normal manner.
1. Once operating, check the system for sluggishness by
changing the setpoint and measuring the time it takes for the
controlled variable to reach the setpoint.
92
McQuay OM-711-1
Software Identification and Configuration
Software Identification
The MicroTech II control system code is made of up to three
different software components. All unit applications include
a main control board application code component that
resides in the main control board (MCB). Then, depending
on the unit configuration, there may be one or two cooling
auxiliary control boards loaded with an application code
component.
The application code in the main control board and any
auxiliary control boards each are assigned a 10-digit base
number. This includes a seven-digit base number, followed
by a three-digit version number.
The software identification numbers the unit was loaded
with at the factory can be determined from a software
identification label. Figure 20 shows a typical software
identification label. The box labeled UNIT SOFTWARE
NUMBER contains the software identification number for
the code in the main control board (MCB). The box labeled
COMPRESSOR SOFTWARE contains the software
identification number for the code in the auxiliary cooling
control board(s) (CCB1, CCB2), when applicable.
Identifying Application Code Using Unit
Keypad/Display
To identify the software identification number for the
application currently loaded into the main control board
(MCB), go to the AHU ID= parameter in the Unit
Configuration menu on the unit keypad/display. The entire
10-digit UNIT SOFTWARE NUMBER displays.
To determine the software identification number for the
application currently loaded into the CCB1 and CCB2
auxiliary cooling control boards, go to the CCB1 ID= and
CCB2 ID= parameters in the Unit Configuration menu on
the unit keypad/display.
Note: Only the sixth through the ninth positions of the
COMPRESSOR SOFTWARE identification number
display.
For example, if a CCB1 board is loaded with version
2506031220 compressor board software, then the CCB1 ID=
parameter displays 3122. If a unit is not equipped with
CCB1 and CCB2 boards, the CCB1 ID= and CCB2 ID=
parameters display three question marks (???).
To determine the software identification number for the
application currently loaded into the EHB1 auxiliary electric
heat control board, go to the EHB1 ID= parameters in the
Unit Configuration menu on the unit keypad/display.
Note: Only the sixth through the ninth positions of the
STAGE ELEC HEAT SOFTWARE identification
number display.
McQuay OM-711-1
For example, if an EHB1 board is loaded with version
2506012210 electric heat board software, then the
EHB1 ID= parameter displays 1221. If a unit is not equipped
with an EHB1 board, the EHB1 ID= parameter displays
three question marks (???).
Figure 20: Software identification label
UNIT SOFTWARE NUMBER
SOFTWARE CONFIGURATION CODE
112100024100101
COMPRESSOR SOFTWARE
250631210
STAGE ELEC HEAT SOFTWARE
ENERGY RECOVERY SOFTWARE
UNIT G.O.- SEQ NUMBER
724062-010
Main Control Board (MCB) Configuration
After the main control board software component is loaded
into the MCB, it must be configured for the specific control
application. This consists of setting the value of 15
configuration variables within the MCB. These variables
define things such as the type of cooling, number of
compressors and cooling stages, and the type of heat. If all of
these items are not set appropriately for the specific unit, the
unit does not function properly. Collectively, these 15
parameters make up a 15-digit string called the Software
Configuration Code. The Software Configuration Code
appears on the Software Identification Label located near the
main control board (MCB) in the main control box. This
label is shown in Figure 20.
The Software Configuration Code currently loaded into a
unit controller also can be determined via the unit
keypad/display by viewing the four menu items under the
Configuration Code menu. The four menu items are
Pos # 1-4=, Pos # 5-8=, Pos # 9-12= and Pos # 13-15=. To
determine the Software Configuration Code in the unit,
combine the values of these four parameters.
For example, if the four parameters read as follows:
Pos # 1-4=1.121, Pos # 5-8=0.002, Pos # 9-12=4.100,
Pos # 13-15=1.01, then the Software Configuration Code in
93
Table 57 lists the configuration string variables including the
position within the string, description of the parameter, the
variable object name, the attribute name, and the applicable
settings for each. The factory default values are shown in
bold font.
from the MCB. In the event of a battery failure, the MCB
includes a data archiving function. Once a day, just after
midnight, all the MCB control parameter settings are
archived to a file stored in the MCB FLASH memory. If the
MCB is powered up with a low or defective battery (or with
the battery removed), the most recently archived data is
restored to the controller.
Main Control Board (MCB) Data Archiving
Note: When this archived data restoration process occurs, it
the unit is 112100024100101. Note that the decimal points in
the values are ignored when constructing the code.
All MCB control parameters and the real time clock settings
are backed up by the MCB battery when power is removed
increases the controller start up and initialization
time period by approximately 75 seconds.
Table 57: Software configuration string
Configuration
string position
Description
Attribute name
(Attribute no.)
Values (default in bold)
1
Unit Type
McQuay_SelfCon. App. McQuay. SC.
Unit State
Unit Type (1579)
0, RA Zone Control
1, RA DAT Control
2, 100% OA Zone Control
3, 100% OA DAT Control
2
Cooling Type
McQuay_SelfCon. App. McQuay. SC.
Cooling
Clg Type (63177)
0, None
1, Compressorized Clg
2, Chilled Water
3
Number of Comps
Number of Cooling Stages
McQuay_SelfCon. App. McQuay. SC.
Cooling
Comp Config (63886)
0, 2 Comp/2 Stage
1, 3 Comp/3 Stage
2, 4Comp/4 Stage
3, 6 Comp/6 Stage
4, 3S & 1L Comp/5 Stage
5, 2S & 2L Comp/6 Stage
4
Economizer
McQuay_SelfCon. App. McQuay. SC.
Damper Control
Econo Type (63953)
0,,Airside
1, Waterside
2, None
5
Head Pressure
Control
McQuay_SelfCon. App. McQuay. SC.
Damper Control
Head Pressure Control
(63963)
0, No
1, Yes
6
Heat Type
McQuay_SelfCon. App. McQuay. SC.
Heating
Htg Type (63530)
0, None
1, Single Staged Local
2, Two Staged Local
4, Steam or Hot Water
7
Not supported by software
8
McQuay_SelfCon. App. McQuay. SC.
DF Cap Ctrl.
Discharge Fan Type
9
10
Not supported by software
VIV/AFD Control Type
SAF
11
12
McQuay_SelfCon. App. McQuay. SC.
DF Cap Ctrl.
Not supported by software
Second Static
Pressure Sensor
13
Communication Option
14
Open Value
15
94
Object name
Bypass Valve Control
Fan Ctrl Type (2296)
DF Cap Ctrl (63317)
-
0
0, Constant Volume
1, Vanes (VIV)
2, AFD
4
0, None
1, Duct Static Control
2, Building Static Control
3, Position
1
McQuay_SelfCon. App. McQuay. SC.
Static P Select
Second P Sensor (63923)
0, None
1, Duct Static Pressure
2, Building Static
Pressure
McQuay_SelfCon
Communication Option
(2159)
0. None
1. BACnet/IP
2. BACnet MS/TP
3. LONMARK SCC
4. LONMARK DAC
McQuay_SelfCon. App. McQuay. SC.
Damper Control
Bypass Valve Cntl (63510)
0
1, Bypass
McQuay OM-711-1
Troubleshooting
In general, when a unit is not operating as expected, the first
step in troubleshooting the MicroTech II control system
should always be to determine the current operating state and
then determine why the unit is currently in that operating
state. The current operating state is determined via the unit
keypad by viewing the UnitStatus= parameter in the System
menu. Once the current operating state is determined, it then
can be assessed whether or not the control is operating
correctly in that state and if not why. The following sections
discuss various scenarios and some steps for troubleshooting
them.
WARNING
Improper troubleshooting can cause equipment
damage, severe personal injury or death.
Troubleshooting must be performed by trained, experienced
technicians only.
Table 58: Fans operate after normal startup sequence, but:
Problem
Check
1. Unit does not leave Fan Only
and enter the Econo or
Cooling operating state.
1.1 Check Clg Status= parameter in System menu:
1. The unit does not enter the Econo operating state unless the Clg Status= parameter
indicates “All Clg” or “Econo.” If it does, refer to Item 1.2 below.
2. The unit does not enter the Cooling operating state unless the Clg Status=
parameter indicates “All Clg” or “Mech Clg.” If it does, refer to Item 1.2 below.
3. The unit does not enter the Econo or the Cooling operating state if the Clg Status=
parameter indicates something other than “All Clg,” “Econo” or “Mech Clg.” If
this is the case, refer to “Clg Status” on page 38 to determine the reason.
1.2. Compare the Ctrl Temp= parameter to the Eff Clg Spt= parameter in the Zone
Cooling menu.
1. The unit does not enter the Econo or Cooling operating state unless the current
value of the Ctrl Temp= parameter is above the Eff Clg Spt= by more than half the
Clg Deadband= parameter in the Zone Cooling menu. If it is, refer to Item 1.3
below.
2. If the current value of the Ctrl Temp= parameter is not above the Eff Clg Spt= by
more than half the Clg Deadband= parameter in the Zone Cooling menu, the Eff
Clg Spt= parameter must be adjusted accordingly to enable cooling operation.
Refer to“Heat/Cool Changeover” on page 62.
1.3Compare the current value of the Disch Air= parameter to the Eff Clg Spt= parameter
in the Discharge Cooling menu.
1. The unit does not initially enter the Econo or Cooling operating state unless the
current value of the Disch Air= parameter is above the Eff Clg Spt= by more than
half the Clg Db= parameter in the Discharge Cooling menu. If it is and the unit
still does not enter either the Econo or Cooling operating state, MCB is likely
defective.
2. If the current value of the Disch Air= parameter is not above the Eff Clg Spt= by
more than half the Clg Db= parameter in the Discharge Cooling menu, the Eff Clg
Spt= parameter must be adjusted accordingly to activate cooling operation. Refer
to“Economizer” on page 64, “Cooling: Multistage” on page 67, or “Cooling:
Modulating” on page 72, (as applicable).
McQuay OM-711-1
95
Table 58: Fans operate after normal startup sequence, but: (continued)
Problem
Check
2. Unit does not leave Fan Only
and enter Heating operating
state.
2.1.Check Htg Status= parameter in System menu:
1. The unit does not enter the Heating operating state unless the Htg Status=
parameter indicates “Htg Ena.” If it does, refer to Item 2.2 below.
2. The unit does not enter the Heating operating state if the Htg Status= parameter
indicates anything other than “Htg Ena.” If this is the case, refer to “Htg Status”
on page 39 to determine the reason.
2.2.Compare the Ctrl Temp= parameter to the Eff Htg Spt= parameter in the Zone
Heating menu.
1. The unit does not enter the Heating operating state unless the current value of the
Ctrl Temp= parameter is below the Eff Htg Spt= by more than half the Htg
Deadband= parameter in the Zone Heating menu. If it is and the unit is equipped
with multi-stage or modulating heat, refer to Item 2.3 below.
2. If the Ctrl Temp= is not below the Eff Htg Spt= by more than half the Htg
Deadband= parameter in the Zone Heating menu, the Eff Htg Spt= parameter
must be adjusted accordingly to enable heating operation. Refer to “Heat/Cool
Changeover” on page 62.
2.3.If the unit is equipped with multi-stage or modulating heat, compare the current value
of the Disch Air= parameter to the Eff Htg Spt= parameter in the Discharge Heating
menu.
1. The unit does not initially enter the Heating operating state unless the current
value of the Disch Air= parameter is below the Eff Clg Spt= by more than half the
Htg Db= parameter in the Discharge Heating menu. If it is and the unit still does
not enter the Heating operating state, MCB is likely defective.
2. If the current value of the Disch Air= parameter is not below the Eff Htg Spt= by
more than half the Htg Db= parameter in the Discharge Heating menu, the Eff Htg
Spt= parameter must be adjusted accordingly to activate heating operation. Refer
to “Heating: Multistage” on page 73 or “Heating: Modulating Temperature
Control” on page 74, (as applicable).
96
McQuay OM-711-1
Table 59: Unit does not startup and run
Problem
Check
1. Unit does not leave the Off Unoc operating
state. (UnitStatus= parameter in the System
menu indicates “Off Unoc” and unit does
not start.)
1.1.Check Occupancy= parameter in Occupancy menu:
1. If the Occupancy = parameter in the Occupancy menu indicates
either “Occ” or “TntOvrd” and the unit remains in the Off Unoc
operating state, MCB is likely defective
2. If the Occupancy = parameter in the Occupancy menu indicates
“Unocc” refer to Item 1.2 below.
1.2.Check Occ Mode= parameter in the Occupancy menu:
1. If the Occ Mode= parameter is set to “Unocc,” the unit starts only if
unoccupied heating (night setback) or unoccupied cooling (night
setup or purge) operation is active. Refer to “Unoccupied Control”
on page 88.
2. If the Occ Mode= parameter is set to “Auto,” the unit starts only if
at least one of the following are true:
a)
Field time clock terminals 101 to 102 on TB2 in the main
control box are made (binary input MCB-BI1 is on). Refer to
“External Time Scheduling” on page 46.
b) Internal time schedule indicates an occupied period. Refer to
“Internal Daily Scheduling” on page 44.
c)
Holiday time schedule indicates an occupied period. Refer to
“Holiday Scheduling” on page 44.
d) One event schedule indicates an occupied period. Refer to
“One Event Scheduling” on page 45.
e)
Network time schedule indicates an occupied period. Refer to
“Network Time Scheduling” on page 46.
f)
Unoccupied heating (night setback) or unoccupied cooling
(night setup or purge) operation is active. Refer to “Unoccupied Control” on page 83.
If any one of items a) through f) is true and the Occupancy=
parameter in the Occupancy menu still indicates “Unocc” and the
unit remains in the “Off Unoc” operating state, MCB is likely
defective.
2. Unit does not leave the Off Sw operating
state. (UnitStatus= parameter in the System
menu indicates “Off Sw” and unit does not
start.)
McQuay OM-711-1
2.1.Check terminals 101 and 104 on TB2 in the main control box:
1. The unit is disabled and remains in the Off Sw operating state when
terminal 101 is made to 104 on TB2 (binary input MCB-BI2 is on).
2. If terminal 101 is not made to 104 on TB2 (binary input MCB-BI2
is off) and the UnitStatus= parameter continues to indicated “Off
Sw,” MCB is likely defective.
97
Table 59: Unit does not startup and run (continued)
Problem
Check
3. Unit does not leave the Off Net operating
state. (UnitStatus= parameter in the System
menu indicates “Off Net” and unit does not
start.)
3.1.Check Ctrl Mode= parameter in System menu:
1. If the Ctrl Mode= parameter in System menu is set to anything
other than “Auto” and the UnitStatus= parameter in the System
menu continues to indicate “Off Net,” refer to Item 3.2.
2. If the Ctrl Mode= parameter in System menu is set to “Auto,” the
UnitStatus= parameter indicates “Off Net” when the Appl Mode=
parameter in the System menu is set to “Off.” If the Appl Mode=
indicates something other than “Off” and the UnitStatus= parameter
in the System menu continues to indicate “Off Net,” refer to Item
3.2.
3.2.Check Emerg Override= parameter in Occupancy menu:
1. The UnitStatus= parameter indicates “Off Net” when the Emerg
Override= parameter is set to “Off.”
2. If the Emerg Override= parameter is set to “Norm” and the UnitStatus=
parameter continues to indicate “Off Net,” MCB is likely defective.
4. Unit does not leave the Off Alm operating
state. (UnitStatus= parameter in the System
menu indicates “Off Alm” and unit does not
start.)
4.1.Press the ALARM key on the unit keypad to Check Active Alarm 1 menu:
1. If the Active Alarm 1 menu indicates an active “fault,” the alarm
condition must be corrected and the “fault” cleared before unit can be
started.
2. If the Active Alarm 1 menu indicates “None” or an alarm type other
than a “fault” and the UnitStatus= parameter in the System menu
continues to indicate “Off Alm,” MCB is likely defective.
5. Unit does not leave the Off Man operating
state. (UnitStatus= parameter in the System
menu indicates “Off Man” and unit does not
start.)
5.1.Check Ctrl Mode= parameter in System menu:
1. If the Ctrl Mode= parameter in System menu is set to “Off,” the
UnitStatus= parameter indicates “Off Man.” The Ctrl Mode=
parameter must be set to something other than “Off” before the unit
will start.
2. If the Ctrl Mode= parameter in System menu is set to anything
other than “Off” and the UnitStatus= parameter in the System menu
still indicates “Off Man,” MCB is likely defective.
98
McQuay OM-711-1
McQuay OM-711-1
99
100
McQuay OM-711-1
McQuay OM-711-1
101
102
McQuay OM-711-1
McQuay Training and Development
Now that you have made an investment in modern, efficient McQuay equipment, its care and operation should be a
high priority. For training information on all McQuay HVAC products, please visit us at www.mcquay.com and click on
Training or call 540-248-9646 and ask for the Training Department.
This document contains the most current product information as of this printing. For the most up-to-date product
information, please go to www.mcquay.com.
13600 Industrial Park Boulevard, Minneapolis, MN 55441 USA (612) 553-5330
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