McQuay® Enfinity™ Horizontal Water Source Heat Pumps R

Installation & Maintenance Data
IM 1049-1
Group: WSHP
Part Number: 910108372
Date: March 2010
McQuay® Enfinity™ Horizontal Water Source Heat Pumps
R-410A Refrigerant
Model CCH, CCW Unit Sizes 007 – 070
®
©2010 McQuay International
Table of Contents
­ odel Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
M
Horizontal Ceiling Unit CCH-CCW . . . . . . . . . . . . . . . . 2
Changing PSC Fan Motor Speed . . . . . . . . . . . . . . . . 19-20
(Optional) ECM Motor - Fan Speed . . . . . . . . . . . . . . . 20
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Receiving, Storage & Handling . . . . . . . . . . . . . . . . . . . . . . 3
Unit Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Filter Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Air Discharge Conversion . . . . . . . . . . . . . . . . . . . . . . 5-6
Ductwork & Attenuation . . . . . . . . . . . . . . . . . . . . . . . 7-8
Ventilation Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Fan Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-10
Cleaning & Flushing . . . . . . . . . . . . . . . . . . . . . . . . 10-11
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-12
Operating Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Additional Information for Initial Start-up . . . . . . . . . . 12
Typical Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . 21-25
MicroTech III Unit Controller with PSC Motor
– 208/230-60-1 Unit Sizes 015-070 . . . . . . . . . . . . . . . 21
MicroTech III Unit Controller with PSC Motor
– 208/230/460/575-60-3 Unit Sizes 024-060 . . . . . . . . 22
MicroTech III Unit Controller with ECM Motor
– 208/230-60-3 Unit Sizes 024-070 . . . . . . . . . . . . . . . 23
MicroTech III Unit Controller with ECM Motor
– 208/230-60-1 Unit Sizes 015-070 . . . . . . . . . . . . . . . 24
MicroTech III Unit Controller with ECM Motor and
Optional Communication Module – 460-60-3
Unit Sizes 024-070 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-19
MicroTech III Controller Terminal Locations
& Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-14
MicroTech III Unit Controller . . . . . . . . . . . . . . . . . . . . 15
Remote Reset Feature . . . . . . . . . . . . . . . . . . . . . . . . . . 15
MicroTech III Controller with Lon Module . . . . . . . . . 16
MicroTech III Controller with BACnet Module . . . . . . 17
MicroTech III Controller with Lon Module on
Board Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Additional Accessories (General) . . . . . . . . . . . . . . . . 26-28
Thermostats & Temperature Sensors . . . . . . . . . . . . 26-27
Pump Restart Relay Kit . . . . . . . . . . . . . . . . . . . . . . . . . 28
Multiple Unit Control . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-33
The in and outs of R-410A . . . . . . . . . . . . . . . . . . . . . . 29
Troubleshooting the Refrigeration Circuit . . . . . . . . . . 30
Typical Refrigeration Cycles . . . . . . . . . . . . . . . . . . . . . 31
Troubleshooting the WSHP Unit . . . . . . . . . . . . . . . . . . 32
Troubleshooting the MicroTech III Unit Controller . . . 33
Enfinity™ Horizontal Ceiling Unit (Size 007 - 070)
W
CCH
1
019
B
E
Y
L
S
Product Category
Discharge Air
W = WSHP
S = Straight
E = End
Product Identifier
WCCH = Ceiling Mounted/Standard Range
WCCW = Ceiling Mounted/Geothermal
Return Air
Design Series
L = Left
R = Right
1 = A Design
2 = B Design
3 = C Design
4 = D Design
Future
(None)
Nominal Capacity
007 = 7,000 BTU/h
009 = 9,000 BTU/h
012 = 12,000 BTU/h
015 = 15,000 BTU/h
019 = 19,000 BTU/h
024 = 24,000 BTU/h
030 = 30,000 BTU/h
036 = 36,000 BTU/h
042 = 42,000 BTU/h
048 = 48,000 BTU/h
060 = 60,000 BTU/h
070 = 70,000 BTU/h
Controls
B - MicroTech III
C - MicroTech III With LonWorks
D - MicroTech III With BACnet
Note: For illustration purposes only. Not all options available with all models.
Please consult McQuay Sales Representative for specific availability.
Page of 36 / IM 1049-1
Voltage
A =115/60/1
E = 208-230/60/1
F = 208-230/60/3
J = 265/60/1
K = 460/60/3
L = 575/60/3
50 Hz
M = 230/50/1
N = 380/50/3
Receiving and Storage
Pre-Installation
WARNING
CAUTION
The installer must determine and follow all applicable
codes and regulations. This equipment presents hazards
of electricity, rotating parts, sharp edges, heat and weight.
Failure to read and follow these instructions can result in
property damage, severe personal injury or death. This
equipment must be installed by experienced, trained
personnel only.
Sharp edges can cause personal injury. Avoid contact
with them.
Upon receipt of the equipment, check carton for visible
damage. Make a notation on the shipper’s delivery
ticket before signing. If there is any evidence of rough
handling, immediately open the cartons to check for
concealed damage. If any damage is found, notify the
carrier within 48 hours to establish your claim and
request their inspection and a report. The Warranty
Claims
Department should then be contacted.
Do not stand or transport the machines on end. For
storing,
each carton is marked with “up” arrows.
In the event that elevator transfer makes up-ended
positioning unavoidable, do not operate the machine
until it has been in the normal upright position for at
least
24 hours.
Temporary storage at the job site must be indoor,
completely sheltered from rain, snow, etc. High or low
temperatures naturally associated with weather patterns
will not harm the units. Excessively high temperatures,
140°F (60°C) and higher, may deteriorate certain plastic
materials and cause permanent damage.
IMPORTANT
This product was carefully packed and thoroughly
inspected before leaving the factory. Responsibility for its
safe delivery was assumed by the carrier upon acceptance
of the shipment. Claims for loss or damage sustained in
transit must therefore be made upon the carrier as follows:
VISIBLE LOSS OR DAMAGE
Any external evidence of loss or damage must be noted
on the freight bill or carrier’s receipt, and signed by the
carrier’s agent. Failure to adequately describe such
external evidence of loss or damage may result in the
carrier’s refusal to honor a damage claim. The form
required to file such a claim will be supplied by the carrier.
CONCEALED LOSS OR DAMAGE
Concealed loss or damage means loss or damage which
does not become apparent until the product has been
unpacked. The contents may be damaged in transit due
to rough handling even though the carton may not show
external damages. When the damage is discovered upon
unpacking, make a written request for inspection by the
carrier’s agent within fifteen (15) days of the delivery date
and file a claim with the carrier.
1. To prevent damage, do not operate this equipment
for supplementary heating and cooling during the
construction period.
2. Inspect the carton for any specific tagging numbers
indicated by the factory per a request from the
installing contractor. At this time the voltage, phase
and capacity should be checked against the plans.
3. Check the unit size against the plans to verify that
the unit is being installed in the correct location.
4. Before installation, check the available ceiling
height versus the height of the unit.
5. Note the location and routing of water piping,
condensate drain piping, and electrical wiring. The locations of these items are clearly marked on
submittal drawings.
6. The installing contractor will find it beneficial
to confer with piping, sheet metal, and electrical
foremen before installing any unit.
Note: Check the unit data plate for correct voltage
with the plans before installing the equipment. Also,
make sure all electrical ground connections are made
in accordance with local code.
7. The contractor shall cover the units to protect the
machines during finishing of the building. This is
critical while spraying fireproofing material on bar
joists, sandblasting, spray painting and plastering. If
plastic film is not available, the shipping carton may
be modified to cover the units during construction.
8. Remove all shipping blocks in the fan wheel.
9. Change the airflow direction from straight discharge
to end discharge or vice versa before the unit is
installed in the ceiling. Refer to the page 5 for Air
Discharge Conversion Instructions.
IM 1049-1 / Page of 36
Unit Location
1. Locate the unit in an area that allows for easy
removal of the filter and access panels. Leave
a minimum of 18" of clearance around the heat
pump for easy removal, and to perform routine
maintenance, or troubleshooting. Provide
sufficient room to make water, electrical and duct
connections.
2. The contractor should make sure that adequate
ceiling panel access exists, including clearance for
hanger brackets, duct collars and fittings at water
and electrical connections.
3. Allow adequate room below the unit for a
condensate trap and do not locate the unit above
pipes.
4. Each unit is suspended from the ceiling by four
threaded rods. The rods are attached to the unit
corners by a hanger bracket through a rubber
isolator. Filter Access
Each unit is shipped with a filter bracket for side filter
removal. For bottom removal push the filter up into top
bracket to gain clearance of bottom bracket and remove
the filter. Also, a sheet metal duct filter retainer can be
fabricated when return air duct work is used.
Figure 1: Hanger Bracket Location Dimensions - Sizes
B
007 thru 060
Control
Box
Coil
Airflow
E
A
Comp
Fan
Assembly
C
D
CAUTION
Do not use rods smaller than shown in Figure 2. The rods
must be securely anchored to the ceiling or to the bar
joists.
Figure 2: Hanger Bracket Details - Sizes 007 thru 060
3/8" Threaded Rod
(By Others)
5. Each unit is furnished with a hanger kit. The kit is
shipped unassembled and includes hanger brackets,
rubber isolators, washers, bolts and lock washers. Lay out the threaded rods per the dimension in
Figures 1 and 2. 6. When attaching the hanger rods to the unit, a double
nut is recommended since vibration could loosen a
single nut. The installer is responsible for providing
the hex nuts when installing hanger rods.
7. Leave minimum 3" (76 mm) extra threaded rod
below the double nuts or minimum 3" (76 mm)
clearance between top of unit and ceiling above to
facilitate top panel removal for servicing.
Page of 36 / IM 1049-1
Bolt & Lock
Washer
Vibration Isolator
Washer
Hex Nuts
(By Others)
UNIT
SIZE
007 – 009
012
015 – 024
030 – 036
042 – 070
A
17.5
17.5
17.5
18.5
25.5
DIMENSIONS (INCHES)
B
C
D
34
22
34
40
22
40
40
22
40
46
23
46
52
30
52
E
20
20
20
21
28
UNIT
SIZE
007 – 009
012
015 – 024
030 – 036
042 – 070
A
445
445
445
470
648
DIMENSIONS (mm)
B
C
D
864 559 864
1016 559 1016
1016 559 1016
1168 584 1168
1321 762 1321
E
508
508
508
533
711
Air Discharge Conversion
Unit sizes 007 thru 070 are stocked as straight
discharge. A straight discharge unit may be converted to
an end discharge by doing the following:
Note: The information covered in this section of the
blower assembly orientation is typical of McQuay
units. Regardless, if you are changing end to straight
or straight to end the blower assembly has to turn
90 degrees and simultaneously rotate 180 degrees
to achieve the proper orientation. Not all McQuay
units will have the same air discharge location but
will have the same general results when following
the instructions.
DANGER
Hazardous Voltage!
Disconnect all electric power including remote
disconnects before servicing. Failure to
disconnect power before servicing can cause
severe personal injury or death.
CAUTION
Sharp edges can cause personal injury. Avoid contact
with them.
3. Remove the access panel to the fan motor by
removing the two (2) screws at the bottom holding
the panel (Figure 3). Remove the piece of insulation
at the bottom on the side of the bottom panel.
4. If the unit being converted is installed and has been
operating, discharge the capacitor. Release the
wire clip shown in Figure 4 to provide slack in the
wires. If necessary remove the wire tie to provide
additional free wire length (Figure 4).
Figure 4: Discharge Capacitor and Release Wire Clip
Capacitor
Release wire clip to
provide slack in wiring
Discharge
Capacitor
5. Remove the screws securing the fan discharge panel
assembly (Figure 3). 1. Turn off power to the unit at the breaker box.
2. Remove the top panel by removing the screws
around the perimeter of the top securing it to the
lower cabinet (Figure 3).
Note: Retain all screws for reinstalling.
Figure 3: Remove Top and Access Panel to Fan Motor
Remove Top
Unit Size 019-024 shown to illustrate
Remove screws around
the perimeter of top
Remove Access
Panel to Fan
Assembly
Remove two (2) screws at
bottom of access panel to
fan motor
Fan Discharge Panel Assembly
(Bottom-Horizontal Orientation)
IM 1049-1 / Page of 36
6. Lift the fan assembly out rotating it 180 degrees and
position it within the opening at the end of the unit
(Figure 5). With the fan motor in the end discharge
position the fan and housing orientation is tophorizontal. A Straight air discharge arrangement the
housing is in the bottom-horizontal orientation.
Figure 5: Lift Out the Fan Assembly Turn 90 degrees and
Rotate 180°
Rotate the Fan Assembly 180º
End Discharge
Arrangement
(Top-Horizontal) Orientation
Position the fan assembly in the
end opening with the fan in the
“top-horizontal” orientation
Straight Discharge Arrangement
(Bottom-Horizontal) Orientation
7. Secure the fan assembly to the unit frame with the
screws removed previously.
8. Reinstall the access panel in the fan motor access
opening (Figure 6).
9. Reinstall the top panel and secure with screws
removed previously.
Remove screws securing the fan assembly to
the cabinet. Note bottom-horizontal orientation
of fan assembly
Figure 6: Reinstall the Top and Access Panel to Motor
Reinstall Top
Note: If installed correctly the fan motor should
be accessible when the fan motor access panel is
removed.
Completed End
Discharge Assembly
Page of 36 / IM 1049-1
Reinstall Access
Panel to Fan Motor
Ductwork & Attenuation
Discharge ductwork is normally used with these
conditioners. Return air ductwork may also be required.
All ductwork should conform to industry standards of
good practice as described in the ASHRAE Systems
Guide.
The discharge duct system will normally consist of a
flexible connector at the unit, a transition piece to the
full duct size, a short run of duct, an elbow without
vanes, and a trunk duct teeing into a branch duct with
discharge diffusers as shown in Figure 7. The transition
piece must not have angles totaling more than 30° or
severe loss of air performance can result. Do not connect the full duct size to the unit without
using a transition piece down to the size of the discharge
collar on the unit. With metal duct material, the sides
only of the elbow and entire branch duct should be
internally lined with acoustic fibrous insulation for
sound attenuation. Glass fiber duct board material is
more absorbing and may permit omission of the canvas
connector. As a general recommendation, the acoustic fibrous
insulation should be at least 1/2 inch thick over the
entire duct run (Figure 8). For better sound attenuation,
line the last five diameters of duct before each register
with a one-inch thick sound blanket. Elbows, tees
and dampers can create turbulence or distortion in the
airflow. Place a straight length of duct, 5 to 10 times the
duct width, before the next fitting to smooth out airflow.
Diffusers that are located in the bottom of a trunk duct
can also produce noise. For this same reason, volume
control dampers should be located several duct widths
upstream from an air outlet.
For Hotel, Motel, Dormitory or Nursing Home
applications that use a single duct discharge, a velocity
of 500 to 600 fpm is suggested. These applications
typically have static pressures as low as 0.05 inches of
water and duct lengths approximately six feet in length. The discharge duct must be fully lined and have a
square elbow without turning vanes. Return air for these
applications should enter through a “low” sidewall filter
grille and route up the stud space to a ceiling plenum. For horizontal heat pumps mounted from the ceiling,
an insulated return plenum is sometimes placed at the
return air opening to further attenuate line-of-sight
sound transmission through return openings.
Figure 7: Suggested Supply Ducting per ASHRAE and SMACNA Publications
Flexible Connector
Ductwork Supported
Independent of Unit
Acoustic/Thermal Lining
3ft. (.9m) to 5ft. (1.5m)
Acoustic/Thermal
Lining
Diffuser
Two 90° Turns
(Ductwork Sized Based on Airflow)
Diffuser
Figure 8: Suggested Return Ducting per ASHRAE and SMACNA Publications
Two 90° Turns Prior to the Intake
(Ductwork Sized Based on Airflow)
Flexible Connector
Acoustic/Thermal
Lining
Acoustic/Thermal
Lining
Ductwork Supported
Independent of Unit
Return Air Intake
Located
Away from the
Unit Blower
Acoustic/Thermal
Lining 10ft. (3 meters)
Flexible Connector
IM 1049-1 / Page of 36
Return air ductwork can be connected to the standard
filter rack. See Figure 9 (side filter removal shown).
The filter rack can be installed for bottom filter removal
or side filter removal by locating the brackets. For side
filter removal the brackets should be located on the
bottom, left side, and top. For bottom filter removal
the brackets should be mounted on the left side top and
right side with the spring clips supporting the filter.
Do not use sheet metal screws directly into the unit
cabinet for connection of supply or return air ductwork,
especially return air ductwork which can hit the drain
pan or the air coil.
Figure 9: Standard 1"(25mm) Filter rack/return air duct
collar
Standard 1" (25mm)
Figure 10: Optional 2"(51mm) Filter rack/return air duct
collar
Tool-less Filter Removal
Page of 36 / IM 1049-1
Ventilation Air
Ventilation may require outside air. The temperature of
the ventilation air must be controlled so that mixture
of outside air and return air entering the conditioner
does not exceed conditioner application limits. It is also
typical to close off the ventilation air system during
unoccupied periods (night setback).
The ventilation air system is generally a separate
building subsystem with distribution ductwork. Simple
introduction of the outside air into each return air
plenum chamber reasonably close to the conditioner air
inlet is recommended. Do not duct outside air directly
to the conditioner inlet. Provide sufficient distance
for thorough mixing of outside and return air. See
Operating Limits on page 12.
Electrical Data
General
1. Verify the compatibility between the voltage and
phase of the available power and that shown on the
unit serial plate. Line and low voltage wiring must
comply with local codes or the National Electrical
Code, whichever applies.
2. Apply correct line voltage to the unit. A 7⁄8"
(22mm) hole and/or a 1-1⁄8" (29 mm) knockout is
supplied on the side of the unit. A disconnect switch
near the unit is required by code. Power to the unit
must be sized correctly and have dual element
(Class RK5) fuses or an HACR circuit breaker
for branch circuit overcurrent protection. See the
nameplate for correct ratings.
3. Three phase 50 cycle units, 380/50-3, require a
neutral wire for 230/50-1 power to the fan circuit.
4. Connect the thermostat/subbase wiring with the
power “off ” to the unit.
5. Field supplied relays installed on the input
terminals W1, W2, Y1, Y2 or G may introduce
electrical noise. Never install relay coils in series
with the inputs.
230 Volt Operation
All 208-230 volt single-phase and three-phase units
are factory wired for 208 volt operation. For 230
phase operation, the line voltage tap on the 24 volt
transformer must be changed. Disconnect and cap the
red lead wire and interchange it with the orange lead
wire on the primary of the 24 volt transformer (sizes
007-060).
Piping
1. All units should be connected to supply and return
piping in a two-pipe reverse return configuration.
A reverse return system is inherently self-balancing
and requires only trim balancing where multiple
quantities of units with different flow and pressure
drop characteristics exist in the same loop. Check
for proper water balance by measuring differential
temperature reading across the water connections. To insure proper water flow, the differential flow
should be 10°F to 14°F (5°C to 8°C) for units in
cooling mode.
A direct return system may also work acceptably,
but proper water flow balancing is more difficult to
achieve and maintain.
2. The piping can be steel, copper or PVC.
3. Supply and return runouts usually join the unit via
short lengths of high pressure flexible hose which
are sound attenuators for both unit operating noise
and hydraulic pumping noise. One end of the hose
should have a swivel fitting to facilitate removal for
service. Hard piping can also be brought directly to
the unit. This option is not recommended since no
vibration or noise attenuation can be accomplished. The hard piping must have unions to facilitate unit
removal. See Figure 11 for typical piping setup.
4. Some flexible hose threaded fittings are supplied
with sealant compound. If not, apply Teflon tape to
assure a tight seal.
Figure 11: (Sizes 007 through 070 shown)
Fan Assembly
Unit sizes 007 through 060 utilize a standard multispeed PSC motor. An ECM motor is standard on unit
size 070 and optional on unit sizes 019 through 060. All
fan motors have integral mounting brackets and thermal
overload protection. The motor is isolated from the
fan housing for minimum vibration transmission. PSC
Fan motors have a terminal strip on the motor body for
simple motor speed change without going back to the
control box. Electrical Access Panel
Hanger Kits (4)
Flex Hoses
Return
Riser
Condensate
Riser
For instructions to adjust PSC fan speed see "Changing
PSC Fan Speed" on pages 19-20. All the fan/motor assemblies have a removable orifice
ring on the housing to accommodate motor and fan
wheel removal without disconnecting the ductwork. The fan housing protrudes through the cabinet allowing
adequate material for connection of flexible duct. Each
model unit is shipped from the factory for maximum
performance and minimum sound requirements. Fan
sound levels and performance can be affected by
external static pressure.
Ball
Valves
Supply Air
Supply
Riser
Note: Do not overtorque fittings. The maximum torque without damage to fittings is 30 foot pounds. If a torque wrench is not available, use as a rule of
thumb, finger-tight plus one quarter turn.
IM 1049-1 / Page of 36
5. Supply and return shutoff valves are required at each
conditioner. The return valve is used for balancing
and should have a “memory stop” so that it can
always be closed off but can only be reopened to the
proper position for the flow required.
6. No unit should be connected to the supply and return
piping until the water system has been cleaned and
flushed completely. After the cleaning and flushing
has taken place, the initial connection should have
all valves wide open in preparation for water system flushing.
7. Condensate piping can be steel, copper or PVC. Each unit includes a condensate connection.
8. The condensate disposal piping must be trapped. The piping must be pitched away from the unit
not less than 1⁄4" per foot. The unit has a 3/4 inch
female pipe fitting on each water source heat pump
to accommodate the condense drain connection. Factory supplied condensate hose assemblies have
a pipe thread fitting to facilitate connection of a
flexible vinyl or steel braided hose.
A complete copper or PVC condense system can
be used. Union fittings in the copper or PVC lines
should be applied to facilitate removal.
Cleaning & Flushing System
1. Prior to first operation of any conditioner, the water
circulating system must be cleaned and flushed of all
construction dirt and debris.
If the conditioners are equipped with water shutoff
valves, either electric or pressure operated, the
supply and return runouts must be connected
together at each conditioner location. This will
prevent the introduction of dirt into the unit. See
Figure 13.
Figure 13: Supply & return runouts connected together
Return Runout
Supply Runout
Mains
Flexible Hose
Runouts Initially
Connected Together
Figure 12: Condensate disposal trapping detail
11⁄2"
(38 mm)
11⁄2"
(38 mm)
Optional Field
Installed Vent
1⁄4" Per Foot
(21 mm Per
Meter)
9. Do not locate any point in the drain system above
the drain connection of any unit.
10.Automatic flow controlled devices must not be
installed prior to system cleaning and flushing.
11.A high point of the piping system must be vented.
12.Check local code for the need for dielectric fittings.
Page 10 of 36 / IM 1049-1
2. Fill the system at the city water makeup connection
with all air vents open. After filling, close all air
vents.
The contractor should start main circulator with
the pressure reducing valve open. Check vents in
sequence to bleed off any trapped air, ensuring
circulation through all components of the system.
Power to the heat rejector unit should be off, and the
supplementary heat control set at 80°F (27°C).
While circulating water, the contractor should
check and repair any leaks in the piping. Drains at
the lowest point(s) in the system should be opened
for initial flush and blowdown, making sure city
water fill valves are set to make up water at the
same rate. Check the pressure gauge at pump
suction and manually adjust the makeup to hold the
same positive steady pressure both before and after
opening the drain valves. Flush should continue for
at least two hours, or longer if required, to see clear,
clean drain water.
3. Shut off supplemental heater and circulator pump
and open all drains and vents to completely drain
down the system. Short circuited supply and return
runouts should now be connected to the conditioner
supply and return connections. Do not use sealers at
the swivel flare connections of hoses.
4. Trisodium phosphate was formerly recommended
as a cleaning agent during flushing. However,
many states and localities ban the introduction of
phosphates into their sewage systems. The current
recommendation is to simply flush longer with warm
80°F (27°C) water.
5. Refill the system with clean water. Test the water
using litmus paper for acidity, and treat as required
to leave the water slightly alkaline (pH 7.5 to 8.5). The specified percentage of antifreeze may also be
added at this time. Use commercial grade antifreeze
designed for HVAC systems only. Do not use
automotive grade antifreeze.
Once the system has been filled with clean water
and antifreeze (if used), precautions should be taken
to protect the system from dirty water conditions. Dirty water will result in system wide degradation of
performance and solids may clog valves, strainers,
flow regulators, etc. Additionally, the heat exchanger
may become clogged which reduces compressor
service life or causes premature failure. 6. Set the loop water controller heat add setpoint
to 70°F (21°C) and the heat rejection setpoint to
85°F (29°C). Supply power to all motors and start
the circulating pumps. After full flow has been
established through all components including the
heat rejector (regardless of season) and air vented
and loop temperatures stabilized, each of the
conditioners will be ready for check, test and startup, air balancing, and water balancing.
Start-up
1. Open all valves to full open position and turn on
power to the conditioner.
2. Set thermostat for “Fan Only” operation by
selecting “Off” at the system switch and “On” at the
fan switch. If “Auto” fan operation is selected, the
fan will cycle with the compressor. Check for proper
air delivery.
3. For those units that have two-speed motors,
reconnect for low speed operation if necessary.
4. Set thermostat to “Cool.” If the thermostat is an
automatic changeover type, simply set the cooling
temperature to the coolest position. On manual
changeover types additionally select “Cool” at the
system switch.
Again, many conditioners have time delays which
protect the compressor(s) against short cycling. After
a few minutes of operation, check the discharge
grilles for cool air delivery. Measure the temperature
difference between entering and leaving water. It
should be approximately 1½ times greater than the
heating mode temperature difference. For example,
if the cooling temperature difference is 15°F (8°C),
the heating temperature difference should have been
10°F (5°C).
Without automatic flow control valves, target a
cooling temperature difference of 10°F to 14°F
(5°C to 8°C). Adjust the combination shutoff/
balancing valve in the return line to a water flow rate
which will result in the 10˚F to 14°F (5°C to 8°C)
difference.
5. Set thermostat to “Heat.” If the thermostat is the
automatic changeover type, set system switch to the
“Auto” position and depress the heat setting to the
warmest selection. Some conditioners have builtin time delays which prevent the compressor from
immediately starting. With most control schemes,
the fan will start immediately. After a few minutes of
compressor operation, check for warm air delivery
at discharge grille. If this is a “cold building” startup, leave unit running until return air to the unit is at
least 65°F (18°C).
Measure the temperature difference between
entering and leaving air and entering and leaving
water. With entering water of 60°F to 80°F (16°C to
27°C), leaving water should be 6°F to 12°F (3.3°C
to 6.6°C) cooler, and the air temperature rise through
the machine should not exceed 35°F (19°C). If the
air temperature exceeds 35°F (19°C), then the water
flow rate is inadequate.
6. Check the elevation and cleanliness of the
condensate line. If the air is too dry for sufficient
dehumidification, slowly pour enough water into the
condensate pan to ensure proper drainage.
7. If the conditioner does not operate, check the
following points:
a. Is supply voltage to the machine compatible?
b. Is thermostat type appropriate?
c. Is thermostat wiring correct?
8. If the conditioner operates but stops after a brief
period:
a. Is there proper airflow? Check for dirty filter, incorrect fan rotation (3-phase fan motors only), or incorrect ductwork.
b. Is there proper water flow rate within temperature limits? Check water balancing; backflush unit if dirt-clogged.
9. Check for vibrating refrigerant piping, fan wheels, etc.
10.Do not lubricate the fan motor during the first year
of operation as it is prelubricated at the factory.
11.Field supplied relays installed on the input terminals
W1, W2, Y1, Y2 or G may introduce electrical
noise. Never install relay coils in series with the
inputs.
IM 1049-1 / Page 11 of 36
Operating Limits
Additional Information For Initial Start-up
This equipment is designed for indoor installation
only. Sheltered locations such as attics, garages,
etc., generally will not provide sufficient protection
against extremes in temperature and/or humidity, and
equipment performance, reliability, and service life may
be adversely affected.
Units are designed to start-up in an ambient of 50°F
(10°C), with entering air at 50°F (10°C), with entering
water at 70°F (21°C), with both air and water flow rates
used in the ISO 13256-1 rating test, for initial start-up
in winter.
Environment
Table 2: Air Limits - °F (English units)
Min. Ambient Air
Normal Ambient Air
Max Ambient Air
Min. Entering Air 1,2
Normal Entering Air db/wb
Max Entering Air db/wb 1,2
Standard Range
Units
Cooling
Heating
50ºF
50ºF
80ºF
70ºF
100ºF
85ºF
50ºF
50ºF
80/67ºF
70ºF
100/83ºF
80ºF
Geothermal Range
Units
Cooling
Heating
40ºF
40ºF
80ºF
70ºF
100ºF
85ºF
50ºF
40ºF
80/67ºF
70ºF
100/83ºF 80ºF
Table 3: Air Limits - °C (SI units)
Min. Ambient Air
Normal Ambient Air
Max Ambient Air
Min. Entering Air 1,2 Normal Entering Air db/wb
Max Entering Air db/wb 1,2 Standard Range
Units
Cooling
Heating
10ºC
10ºC
27ºC
21ºC
38ºC
29ºC
10ºC
10ºC
27/19ºC
21ºC
38/28ºC
27ºC
Table 4: Water - °F (English units)
Min. Entering Water 1,2 Normal Entering Water
Max Entering Water
Standard Range
Units
Cooling
Heating
55ºF
55ºF
85ºF
70ºF
110ºF
90ºF
Geothermal Range
Units
Cooling
Heating
5ºC
5ºC
27ºC
21ºC
38ºC
29ºC
10ºC
5ºC
27/19ºC
21ºC
38/28ºC
27ºC
Geothermal Range
Units
Cooling
Heating
30ºF
20ºF
77ºF
40ºF
110ºF
90ºF
Table 5: Water - °C (SI units)
Min. Entering... Water 1,2 Normal Entering Water
Max Entering Water
Standard Range
Units
Cooling
Heating
13ºC
13ºC
29ºC
21ºC
43ºC
32ºC
Geothermal Range
Units
Cooling
Heating
-1ºC
-6ºC
25ºC
4ºC
43ºC
32ºC
At ARI flow rate.
 Maximum and minimum values may not be co bined. If one value is at maximum or minimum, the other two conditions may not exceed the normal condition for standard units. Extended range
units may combine any two maximum or minimum conditions, but
not more than two, with all other conditions being normal conditions.
Page 12 of 36 / IM 1049-1
Standard Range units CCH
ote: This is not a normal or continuous operating
N
condition. It is assumed that such a start-up is for
the purpose of bringing the building space up to
occupancy temperature.
Geothermal Range units CCW
Geothermal heat pump units are designed to start-up
in an ambient of 40°F (5°C), with entering air at 40°F
(5°C), with entering water at 25°F (-4°C), with both air
and water at flow rates used in the ISO 13256-1 rating
test, for initial start-up in winter.
ote: This is not a normal or continuous operating
N
condition. It is assumed that such a start-up is for
the purpose of bringing the building space up to
occupancy temperature.
Table 6: MicroTech® III Unit Controller Terminals Locations and Descriptions
24
24 VAC Power Input
H7 - 6
Red-Green-Yellow LED Common
H1 - 2
C
24 VAC Common
H8 - 1
1
Isolation Valve/Pump Request Relay N/O
H2 - 1
SL1
Fan Output - Switched L1
H8 - 2
Isolation Valve/Pump Request Relay N/C
H2 - 2
Blank Terminal
H8 - 3
24 VAC Common
H2 - 3
N
Fan Neutral
H9 - 1
Return Air Temperature Signal
H3 - 1
HP1-1
High Pressure Switch 1 Input Terminal 1
H9 - 2
Return Air Temperature Common
H3 -2
HP1-2
High Pressure Switch 1 Input Terminal 2
TB1 - 1
1
Room Sensor LED Output
H4 - 1
Discharge Air Temp Common
TB1 - 2
2
Fan Mode / Heat-Cool-Auto Input
H4 - 2
Discharge Air Temp Signal
TB1 - 3
3
Setpoint Adjust Input
H4 - 3
Leaving Water Temp Common
TB1 - 4
4
Room Temperature Sensor / Tenant Override
H4 - 4
Leaving Water Temp Signal
TB1 - 5
5
DC Signal Common
H5 - 1
24 VAC
H1 - 1
1
1
I/O Exp Module Common (Gnd)
Test-1
R
H5 - 2
I/O Exp Module Common (Gnd)
Test-2
W2
Heat Stage 2 Input
H5 - 3
I/O Exp Module +5 VDC
Test-3
W1
Heat Stage 1 Input
H5 - 4
I/O Exp Module SPI CE1
Test-4
Y2
Cool Stage 2 Input
H5 - 5
I/O Exp Module SPI CLK
Test-5
Y1
Cool Stage 1 Input
H5 - 6
I/O Exp Module SPI OUT
Test-6
G
Fan
H5 - 7
I/O Exp Module SPI IN
TB2 - 1
R
24 VAC
H5 - 8
I/O Exp Module +12 VDC
TB2 - 2
A
Alarm Output
H5 - 9
I/O Exp Module 24 VAC
TB2 - 3
W2
Heat Stage 2 Input
H5 - 10
I/O Exp Module 24 VAC
TB2 - 4
W1
Heat Stage 1 Input
H5 - 11
Spare
TB2 - 5
Y2
Cool Stage 2 Input
H5 - 12
Spare
TB2 - 6
Y1
Cool Stage 1 Input
H6 - 1
Condensate Overflow Signal Input
TB2 - 7
G
Fan Input
H6 - 2
1
Low Temp 1 Sensor Common
TB2 - 8
O
Tenant Override Input
H6 - 3
Low Temp 1 Sensor Signal
TB2 - 9
C
24 VAC Common
H6 - 4
Low Pressure Switch 1 Source Voltage
TB3 - 1
E
Mark IV Emergency Shutdown Input
H6 - 5
Low Pressure Switch 1 Signal
TB3 - 2
U
Mark IV Unoccupied/Occupied Input
H6 - 6
Reversing Valve 1 Common
L1 - 1
L1 - 1
Line Voltage Terminal 1
H6 - 7
Reversing Valve 1 Output
L1 - 2
L1 - 2
Line Voltage Terminal 2
H7 - 1
1
Dummy Terminal
L1 - 3
L1 - 3
Line Voltage Terminal 3
H7 - 2
Dummy Terminal
N1
N1
Neutral Terminal 1
H7 - 3
Red LED Output
N2
N2
Neutral Terminal 2
H7 - 4
Green LED Output
N3
N3
Neutral Terminal 3
H7 - 5
Yellow LED Output
Table 7: Configuration Jumper Settings
Jumper
Description
Options
Open for normal operation mode
JP1
Mode
Shorted for service/test operation mode
JP2 Fan operation only applies to Open for continuous fan operation
network controls
Shorted for cycling fan operation
Open for water freeze protection
JP3
Freeze protection
Shorted for antifreeze protection
JP4
Future spare
Future spare
JP5
Set point adjustment range only
Open for adjustment range of -3.0° to +3.0° F
applies to network controls with a Shorted for 50° to 90° F adjustment range
room temperature sensor
Open for thermostatic room control
JP6
Room control type
Shorted for room temperature sensor control, MicroTech III only
JP7
Future spare
Future spare
JP8
Future spare
Future spare
IM 1049-1 / Page 13 of 36
Note: A random start delay time between 180 and
240 seconds is generated at power up.
Figure 14: Location of Configuration Jumpers on the
MicroTech III Unit Controller
Figure 13: MicroTech III Unit Controller Terminal
Locations
The IV/PR(H8) terminals of the
MicroTech III unit controller are
used for motorized valve / pump
restart. This terminal passes a
voltage signal whenever the unit
compressor is turned on. This
signal is detected by a pump
restart relay providing a N.O. or
N.C. set of contacts for heat pump
loop circulation pump or motorized
valve control. When used with a
system control (by others), the
relay operation accommodates
turning off circulation pumps
during unoccupied periods with
a safety override dependent,
at minimum, on WSHP’s need.
The IV/PR(H8) terminals may be
“daisy chained” between
200 units.
Page 14 of 36 / IM 1049-1
MicroTech® III Unit Controller
The MicroTech III Unit Controller includes built-in
features such as random start, compressor time delay,
shutdown, condensate overflow protection, defrost
cycle, brownout, and LED/fault outputs. Table 8 shows
the LED and fault output sequences.
The unit has been designed for operation with a
microelectronic wall thermostat selected by the
manufacturer. Do not operate the unit with any other
type of wall thermostat.
Each unit has a printed circuit board control system. The
low voltage output from the low voltage terminal strip
is AC voltage to the wall thermostat. R is A/C voltage
output to the wall stat.
The 24 volt low voltage terminal strip is set up so R-G
energizes the fan, R-Y1 energizes the compressor for
cooling operation, R-W1 energizes the compressor and
reversing valve for heating operation. The reversing
valve is energized in the heating mode. The circuit
board has a fan interlock circuit to energize the fan
whenever the compressor is on if the thermostat logic
fails to do so. The output to the wall stat is AC current. Terminal (R)
on the wall stat can be connected to terminal (R) on the
PC board for AC voltage.
R = AC current
R to G = fan only
R to Y1 = cooling
R to W1 = heat
The MicroTech III unit controller has a lockout circuit
to stop compressor operation if any one of its safety
switches opens (high pressure switch and low pressure
switch on unit sizes 024 through 070). If the low
temperature switch opens, the unit will go into the
cooling mode for 60 seconds to defrost any slush in the
water-to-refrigerant heat exchanger. After 60 seconds
the compressor is locked out. If the condensate sensor
detects a filled drain pan, the compressor operation
will be suspended only in the cooling mode. The unit is
reset by opening and closing the disconnect switch on
the main power supply to the unit in the event the unit
compressor operation has been suspended due to low
temperature (freezestat) switch, high pressure switch,
or low pressure switch on unit sizes 019 thru 070. The
unit does not have to be reset on a condensate overflow
detection.
The MicroTech III unit controller fault output sends a
signal to an LED on a wall thermostat. Table 8 shows
for which functions the fault output is “on” (sending a
signal to the LED).
Table 8: MicroTech III unit controller LED & fault outputs
Status LED’s
Thermostat Alarm Light
Mode / Fault
Yellow Green Red
Output-Terminal “A”
Occupied, Bypass,
Standby, or Tenant Off
On
Off
Energized
Override
Unoccupied
On
On
Off
Energized
Condensate Overflow
On
Off
Off
De-engergized
High Pressure 1 Fault
Off
Off Flash
De-energized
Low Pressure 1 Fault
Off
Off
On
De-energized
Low Temperature 1 Fault Flash
Off
Off
De-energized
Brownout Off
Flash Off
De-energized
Emergency Shutdown
Off
Flash Off
De-energized
Room/Return Air or Low
Flash Flash On
De-engergized
Temp Sensor 1 Failure
Service Test Mode Enabled 1
On
On
Off
De-energized
Serial EEPROM
Corrupted
On
On
On
De-energized
Network “Offline”
Received
Off
Off
Off
De-enegized
1Compressor
relay/compressor terminal is labeled COMP, switched line of the
same electric input as any of the L1 terminals.
Remote Reset Feature
The Remote Reset feature provides the means to
remotely reset automatic lockouts generated by highpressure and/or low-temperature (in heating) faults. When the MicroTech III unit controller is in automatic
lockout due to one of these faults, and the cause of
the fault condition has been alleviated, energizing
the O-terminal for 10 seconds or more will force the
MicroTech III unit controller to clear the lockout. A
unit power cycle can also be used to clear an automatic
lockout if the conditions causing the fault have been
alleviated.
The Intelligent reset feature helps to minimize nuisance
trips of automatic reset lockouts caused by highpressure and/or low-temperature (in heating) faults. This
feature clears faults the first two times they occur within
a 24-hour period and triggers an automatic lockout on
the 3rd fault. The retry count is reset to zero every 24
hours.
The MicroTech III unit controller has built-in night
setback operation. A “grounded’ signal to the “U”
terminal on TB3 of the unit control puts the unit into
the unoccupied mode for night setback operation. Fan operation terminates and unit control will only
respond to signal at the W2 terminal. Daytime heating
and cooling operation is locked out. +24VAC to W2
energizes the compressor and reversing valve for
heating operation. Night setback operation can be
overridden for two hours by energizing the O on the
TB2 terminal of the unit control for 3 seconds. Day
thermostat setpoints then control the heating and
cooling operation. The MicroTech III unit controller
also accommodates shutdown operation on receipt of a
“grounded” signal to the “E” input, respectively, on TB3
input terminal of the unit control.
IM 1049-1 / Page 15 of 36
MicroTech III Controller With LonWorks®
Communication Module
Each unit controller orchestrates the following unit operations:
This manual covers the installation of a McQuay
Horizontal Ceiling Hung Unit - Model CCH, CCW
Water Source Heat Pump. For installation and operation
information on LonWorks Communication Module and
other ancillary control components, see:
■ Enable fan and compressor operation.
• IM 927 - MicroTech III Water Source Heat Pump
LonWorks Communication Module
• IM 933 - LonMaker Integration Plug-in Tool: For
use with the MicroTech III Unit Controller
• IM 955 - MicroTech III Wall Sensor for use with
Microtech III Unit Controller
Figure 15: LonWorks Communication Module
The LonWorks communication module will plug
into the Microtech III unit controller at the CN_LON1
Header (see figure 17 on page 18).
Each McQuay water source heat pump can be equipped
with a LonWorks communication module. The controller is microprocessor-based and is designed to communicate over a LonWorks communications network. The
unit controller is factory programmed and tested with all
the logic required to monitor and control the unit. The
wall thermostat sets the unit mode of operation. The unit
controller monitors water and air temperatures, and can
communicate fault conditions to a LonWorks communications network.
The MicroTech III unit controller with communication
module includes a unit-mounted return air, discharge
air and leaving water temperature sensor. Wall mounted
temperature sensors include setpoint adjustment and
tenant override. The user has the capability of substituting the wall sensor with a duct-mounted return air
sensor.
Page 16 of 36 / IM 1049-1
■ Enable heating and cooling to maintain setpoint
based on a room sensor.
■ Monitor all equipment protection controls.
■ Monitor discharge air temperature.
■ Monitor leaving water temperature.
■ Relay status of all vital unit functions.
■ Support optional control outputs.
An amber, on-board status LED aids in diagnostics by
indicating the water source heat pump operating mode
and alarm conditions. If there are no current alarm conditions, the LED will indicate the unit operating mode. If there are one or more alarm conditions present, the
LED will flash to indicate an alarm condition.
MicroTech III heat pumps with a MicroTech III unit
controller are LonMark certified and designed to be
linked with a centralized building automation system
through a LonWorks communications network for
centralized scheduling and management of multiple
heat pumps. Wall-mounted room sensors are available
to control the heating and cooling operation of each
MicroTech III Water Source Heat Pump Unit Controller. Available room sensors include: room sensor with LED
status and tenant override button, room sensor with
LED status, timed-override button, room sensor with
LED status, timed-override button, and setpoint adjustment, and room sensor with LED status, timed-override
button, setpoint adjustment.
The MicroTech III water source heat pump unit controller provides control of McQuay water source heat
pumps. The controller enables the mode of operation,
monitors the water and air temperatures, and indicates
fault conditions. Each unit controller is factory programmed, wired, and tested for effective operation of
your McQuay water source heat pump.
The MicroTech III water source heat pump controller
uses LonWorks technology. One of the following two
versions of the application software is loaded into the
controller at the factory.
LonMark® 3.4 certified application code is the current
standard application code for MicroTech III units. MicroTech III Controller with BACnet
Communication Module
Figure 16: MicroTech III BACnet Water Source Heat
Pump Snap-in Communication Module
For installation and operation information on MicroTech
III unit controller and other ancillary components, see:
• IM 928 - MicroTech III BACnet Communication
Module
• OM 931 - MicroTech III Unit Controller for Water
Source Heat Pumps Operation and Maintenance
Manual
• IM 955 - MicroTech III Wall Sensor For use with
Microtech III Unit Controller
McQuay water source heat pumps are available with
McQuay BACnet MS/TP communication module that
is designed to communicate over a BACnet MS/TP
communications network to a building automation
system (BAS). It can be factory or field-installed.
MicroTech III Unit Controller with BACnet MS/TP
Communication Module orchestrates the following unit
operations:
 Enable heating and cooling to maintain setpoint
based on a room sensor
 Enable fan and compressor operation
 Monitors all equipment protection controls
The unit controller is programmed and tested with
all the logic required to monitor and control the
unit. An optional wall sensor may be used with the
communication module to provide limited local control
of the water source heat pump. The unit controller
monitors water and air temperatures and passes
information to the communication module. The module
communicates with the BAS, to provide network control
of the water source heat pump.  Monitors room and discharge air temperatures
 Monitors leaving water temperature
 Relays status of all vital unit functions
The MicroTech III unit controller with communication
module includes:
 A unit-mounted return air sensor*
 A unit-mounted discharge air sensor*
The module makes operational data and commands
available on a communications network using BACnet
objects and properties:
 The network cable is a shielded twisted-pair cable
 Network communications run up to 76.8 Kbps
 DIP switches on the controller enable the MS/TP
MAC address to be set in the range 0-127
 Four green status LEDs on the communication
module indicate communication activity on the
MS/TP communication network and with the unit
controller
 A leaving water temperature sensor*
* Discharge air and return air sensors must be fieldinstalled per IM 956.
The communication module provides access to setpoints
for operational control
Available wall sensors include:
 Room sensor with LED status and tenant override
button
 Room sensor with LED status, tenant override button, and ±3°F setpoint adjustment
 Room sensor with LED status, tenant override
button, 55° to 90°F setpoint adjustment
IM 1049-1 / Page 17 of 36
Figure 17: LonWorks® Communication Module Placement on MicroTech™ III Unit Controller
Page 18 of 36 / IM 1049-1
Changing PSC Fan Motor Speed
Figure 19: Sizes 019 through 036 (208/230-60-1), (265-60-1)
The fan motor can be changed from high to low speed
or vice versa by interchanging the wires on the black
and red labeled terminals on the motor terminal block.
WARNING
Hazardous Voltage!
The installer must determine and follow
all applicable codes and regulations. This
equipment presents hazards of electricity,
rotating parts, sharp edges, heat and weight.
Failure to read and follow these instructions
can result in property damage, severe personal
injury or death.
CAUTION
Unit Size 030 and 036 (460-60-1)
Fan motors on unit sizes 030 and 036, 460-60-1 (Figure
20) have a four-position terminal block. High and low
speeds can be interchanged by switching the wires on
the black and red terminals.
Figure 20: Sizes 030 through 036 (460-60-1)
Sharp edges can cause personal injury. Avoid contact
with them.
Table 9: Fan Motor Voltage and Terminal Slots
CCH, CCW R410-A
Volts and Number of Terminal Slots
Unit Size
208V
460V
575V Factory
Fan Speed
007
n/a
n/a
n/a
n/a
009
n/a
n/a
n/a
Low
012
n/a
n/a
n/a
High
015
4
–
–
Low
019
4
–
–
Low
024
4
4
–
High
030
4
4
–
High
036
4
6
–
High
042
4
6
6
High
048
4
6
6
Low
060
4
6
6
High
Unit Size 007 through 012 (115-60-1), (208/230-60-1) and
(265-60-1)
Unit Size 042 through 060
Fan motors on unit sizes 042-060 (Figure 21 & 22) have
a six-position terminal block. Motors for these sizes are
factory wired for high speed. For low speed operation,
move the black terminal (3) to the red terminal (6) and
the black and blue terminals (3 & 4) receive a jumper.
Figure 21: Sizes 042-060 (460/575-60-1) High Speed
To change between high and low speed; interchange the
red and black wires.
Figure 18: Sizes 009 through 012 (115/60-1,
(208/230-60-1), (265-60-1)
Figure 22: Sizes 042-060 (460/575-60-1) Low Speed
Unit Size 015 through 036 (208/230-60-1) and (265-60-1)
Fan motors on unit sizes 019-036, in both 208/230-60-1
and 265-60-1 voltages (Figure 19) have a four-position
terminal block. To change between high and low speed,
interchange the red and black wires.
IM 1049-1 / Page 19 of 36
Unit Size 042 through 060 (265-60-1), (208/230-1) &
(208/230-3)
Start-up
CAUTION
Fan motors on unit sizes 042-060 in voltages 265-60-1,
208/230-1 and 208/230-3 (Figure 23) all have a fiveposition terminal block. In order to change between
high and low speed, interchange the wires on the black
and red terminals.
Figure 23: Sizes 042-060 (265-60-1), (208/230-1) (208/230-3)
Units must be checked for water leaks upon initial water
system start-up. Water leaks may be a result of mishandling or damage during shipping. Failure by the installing
contractor to check for leaks upon start-up of the water
system could result in property damage.
1. Open all valves to full open position and turn on
power to the unit.
2. Set the thermostat for "Fan Only" operation by
selecting "Off" at the system switch and "On" at the
fan switch. If "Auto" fan operation is selected, the
fan will cycle with the compressor. 3. For those units that have two-speed motors,
reconnect for low speed operation if necessary.
Unit Size 024 through 036 (208/230-3)
Fan motors on unit sizes 024-036 in voltages 208/2303 (Figure 24) all have a four-position terminal block. In order to change between high and low speed,
interchange the wires on the black and red terminals.
Figure 24: Sizes 024-036 (208/230-3)
4. Set thermostat to “Cool.” If the thermostat is an
automatic changeover type, simply set the cooling
temperature to the lowest temperature. On manual
changeover types, additionally select “Cool” at the
system switch.
Notes:
All motors have a wiring label that is keyed for proper
wiring operation. Check unit wiring diagram (on
electrical access panel) for proper unit operation.
Not all labels are the same.
Units leaving the factory are wired for high or low
fan speed (see table 9 on page 19 for fan speed
settings).
Label is located on the back of the terminal block.
(Optional) ECM Motor
The ECM motor will maintain the rated airflow as
static pressure increases or decreases within the unit’s
operating range. Contact the factory at 315-253-2771 or
800-432-1342 if an alternate airflow setting is required.
Page 20 of 36 / IM 1049-1
Again, many units have time delays help protect the
compressor(s) against short cycling. After a few minutes of operation, check the
discharge grilles for cool air delivery. Measure
the temperature difference between entering and
leaving water. It should be approximately 1-1⁄2
times greater than the heating mode temperature
difference. For example, if the cooling temperature
difference is 15°F (8°C), the heating temperature
difference should be 10°F (5°C).
Without automatic flow control valves, target a
cooling temperature difference of 10°F to 14°F (5°C
to 8°C). Adjust the combination shutoff/balancing
valve in the return line to a water flow rate which
will result in the 10˚F to 14°F (5°C to 8°C)
difference.
5. Set thermostat to “Heat.” If the thermostat is the
automatic changeover type, set system switch to
the “Auto” position and depress the heat setting
to the highest temperature. Some units have builtin time delays which prevent the compressor
from immediately starting. With most control
schemes, the fan will start immediately. After a few
minutes of compressor operation, check for warm
air delivery at discharge grille. If this is a “cold
building” start-up, leave unit running until return air
to the unit is at least 65°F (18°C).
Typical Wiring Diagram
Figure 25: MicroTech III Unit Controller with PSC Motor – 208/230-60-1 Unit Sizes 015-060
Drawing No. 668991002
Table B
208V RED
230V ORG
Legend
Item
Description
C1
C2
CC
CM
COS
DAT
EWT
HP
ISO-NO
LED1
LP
SLTS
LWT
MIII
R1
RAT
RV
TB1
X1
_____
_ _ _ _
Capacitor-Compressor
Capacitor-Fan
Compressor - Contactor
Compressor - Motor
Condensate Overflow Sensor
Discharge Air Temp Sensor
Entering Water Temp Sensor
High Pressure Switch
Isolation Valve - Normally Open
LED Annunciator / Harness
Low Pressure Switch
Suction Line Temp Sensor
Leaving Water Temp Sensor
MicroTech III Main Board
Relay - Fan Motor
Return Air Temp Sensor
Reversing Valve Solenoid
Power Terminal Block
Primary 24VAC Transformer
Standard Unit Wiring
Optional Wiring (by others)
Notes:
1.
Main board jumpers:
JP3 Geothermal
Transformer:
Unused wire to be capped.
Note: The gray tinted areas in the wiring diagram; Leaving Water (LWT), Discharge Air (DAT) and Return Air (RAT) Temperature
sensors are shipped or are field installed on units configured with a communication module.
*Wiring diagrams are typical. For the latest drawing version refer to the wiring diagram located on the inside of the controls access
panel of the unit.
IM 1049-1 / Page 21 of 36
Typical Wiring Diagram
Figure 26: MicroTech III Unit Controller with PSC Motor – 208/230/460/575-60-3 Unit Sizes 024-060
Drawing No. 668991202
Legend
Table B
208V RED
230V ORG
460VBLK/RED
575V BLUE
Item
Description
C1
C2
CC
CM
COS
DAT
EWT
HP
ISO-NO
LED1
LP
SLTS
LWT
MIII
R1
RAT
RV
TB1
X1
_____
_ _ _ _
Capacitor-Compressor
Capacitor-Fan
Compressor - Contactor
Compressor - Motor
Condensate Overflow Sensor
Discharge Air Temp Sensor
Entering Water Temp Sensor
High Pressure Switch
Isolation Valve - Normally Open
LED Annunciator / Harness
Low Pressure Switch
Suction Line Temp Sensor
Leaving Water Temp Sensor
MicroTech III Main Board
Relay - Fan Motor
Return Air Temp Sensor
Reversing Valve Solenoid
Power Terminal Block
Primary 24VAC Transformer
Standard Unit Wiring
Optional Wiring (by others)
Notes:
1.
Main board jumpers:
JP3 Geothermal
Transformer:
Unused wire to be capped.
Note: The gray tinted areas in the wiring diagram; Leaving Water (LWT), Discharge Air (DAT) and Return Air (RAT) Temperature
sensors are shipped or are field installed on units configured with a communication module.
*Wiring diagrams are typical. For the latest drawing version refer to the wiring diagram located on the inside of the controls access
panel of the unit.
Page 22 of 36 / IM 1049-1
Typical Wiring Diagram
Figure 27: MicroTech III Unit Controller with ECM Motor – 208/230-60-3 Unit Sizes 024-070
Drawing No. 910104890
Table B
208V RED
230V ORG
Legend
Item
Description
CC
CM
COS
HP
ISO-NC
ISO-NO
LED1
LP
SLTS
LWT
MIII
RAT
RV
X1
_____
_ _ _ _
Compressor - Contactor
Compressor - Motor
Condensate Overflow Sensor
High Pressure Switch
Isolation Valve - Normally Closed
Isolation Valve - Normally Open
LED Annunciator / Harness
Low Pressure Switch
Suction Line Temp Sensor
Leaving Water Temp Sensor
MicroTech III Main Board
Return Air Temp Sensor
Reversing Valve Solenoid
Transformer
Standard Unit Wiring
Optional Wiring (by others)
Notes:
1.
Main board jumpers:
JP3 Geothermal
Transformer:
Unused wire to be capped.
Note: The gray tinted areas in the wiring diagram; Leaving Water (LWT) and Discharge Air (DAT) Temperature sensors are
shipped or are field installed on units configured with a communication module.
*Wiring diagrams are typical. For the latest drawing version refer to the wiring diagram located on the inside of the controls
access panel of the unit.
IM 1049-1 / Page 23 of 36
Typical Wiring Diagram
Figure 28: MicroTech III Unit Controller with ECM Motor – 208/230-60-1 Unit Sizes 015-070
Drawing No. 919194871
Table B
208V RED
230V ORG
Legend
Item
Description
C1
CC
CM
COS
DAT
EWT
HP
ISO-NC
ISO-NO
LED1
LP
SLTS
LWT
MIII
R1
RAT
RV
X1
_____
_ _ _ _
Capacitor-Compressor
Compressor - Contactor
Compressor - Motor
Condensate Overflow Sensor
Discharge Air Temp Sensor
Entering Water Temp Sensor
High Pressure Switch
Isolation Valve - Normally Closed
Isolation Valve - Normally Open
LED Annunciator / Harness
Low Pressure Switch
Suction Line Temp Sensor
Leaving Water Temp Sensor
MicroTech III Main Board
Relay - Fan Motor
Return Air Temp Sensor
Reversing Valve Solenoid
Transformer
Standard Unit Wiring
Optional Wiring (by others)
Notes:
1.
Main board jumpers:
JP3 Geothermal
Transformer:
Unused wire to be capped.
Note: The gray tinted areas in the wiring diagram; Leaving Water (LWT) and Discharge Air (DAT) Temperature sensors are
shipped or are field installed on units configured with a communication module.
*Wiring diagrams are typical. For the latest drawing version refer to the wiring diagram located on the inside of the controls
access panel of the unit.
Page 24 of 36 / IM 1049-1
Typical Wiring Diagram
Figure 29: MicroTech III Unit Controller with ECM Motor and Optional Communication Module – 460-60-3
Unit Sizes 024-070
Drawing No. 910102101
Table B
460V/NBLK/RED
Legend
Item
Description
CC
CM
COS
HP
ISO-NC
ISO-NO
LED1
LP
SLTS
LWT
MIII
RAT
RV
X1
_____
_ _ _ _
Compressor - Contactor
Compressor - Motor
Condensate Overflow Sensor
High Pressure Switch
Isolation Valve - Normally Closed
Isolation Valve - Normally Open
LED Annunciator / Harness
Low Pressure Switch
Suction Line Temp Sensor
Leaving Water Temp Sensor
MicroTech III Main Board
Return Air Temp Sensor
Reversing Valve Solenoid
Transformer
Standard Unit Wiring
Optional Wiring (by others)
Notes:
1.
Main board jumpers:
JP3 Geothermal
Transformer:
Unused wire to be capped.
3-phase service with a neutral is required
for ECM fan motor and 460 VAC
operation.
Note: The gray tinted areas in the wiring diagram; Leaving Water (LWT) and Discharge Air (DAT) Temperature sensors are
shipped or are field installed on units configured with a communication module.
*Wiring diagrams are typical. For the latest drawing version refer to the wiring diagram located on the inside of the controls
access panel of the unit.
IM 1049-1 / Page 25 of 36
Thermostat Connections
Figure 30: 7-Day Programmable Electronic Thermostat
(P/N 668375301)
MicroTech III Unit Control Board
Low Voltage Terminal Strip (Circuit 1)
TB2
Thermostat
Terminals
24VAC Common
C
Tenant Override
O
-
Fan
G
+
C
R
Cool 1
Y1
Cool 2
W1
Y2
Heat 1
Y1
W1
Heat 2
W2
W2
Alarm Output
A
24VAC
R
Y2
4. Install two strand shielded wire between remote
sensor and thermostat. Shielded wire must be used.
Do not run remote sensor wire in conduit with other wires.
• Wire 1 should run between the S1 terminal on the
thermostat and the S1 terminal on the remote sensor
• Wire 2 should run between the S2 terminal on the
thermostat and the S2 terminal on the remote sensor
• Connect the shielding of the wire to the S2 terminal
on the thermostat
5. Disable the main sensor (R12) on the thermostat by
cutting it from the circuit board.
Figure 32: Optional Remote Sensor Wiring
G
Thermostat
Remote Sensor
Notes: Includes Thermostat and Wall Plate.
S1 S2
Refer to the installation, operation & application guide
(LIA265) for thermostat 668375301.
S1 S2
Figure 31: Non-Programmable Electronic Thermostat
(P/N 668375401)
Cut R12 from
circuit board
MicroTech III Unit Control Board
Low Voltage Terminal Strip (Circuit 1)
TB2
Wire 2
Wire 1
24VAC Common
C
Tenant Override
O
-
MicroTech III Wall-Mounted Room Temperature Sensors
(Kit P/N 669529101, 669529201, 669529001)
Fan
G
+
Figure 33: MicroTech III Wall-Mounted Room
Cool 1
Y1
Cool 2
Y2
Heat 1
W1
Heat 2
W2
Alarm Output
A
24VAC
R
Thermostat
Terminals
C
R
W1
Temperature Sensors (669529201 Not Shown)
Y1
W2
Y2
G
O
*Override (Optional)
Note: Includes Thermostat and Wall Plate.
Refer to the installation, operation & application guide
(LIA266) for thermostat 668375401.
*When remote reset of a lockout condition is required
at the wall thermostat, it will be necessary to utilize
a conductor between terminal "O" on the wall
thermostat to terminal "O" on the MicroTech III unit
controller (non-programmable stat only).
Optional Remote Sensor (P/N 66720401)
1. Remove cover from remote sensor housing.
2. Select an appropriate location for mounting the
remote sensor.
3. Mount remote sensor unit using hardware provided.
Page 26 of 36 / IM 1049-1
Sensor 669529101
Sensor 669529201 Not Shown
Sensor 669529001
General
Microtech III Wall-Mounted Room Temperature
Sensors provide electronic sensing of room
temperatures at wall locations. All sensor models feature
a thermistor (10kΩ) and a green LED for unit status.
Tenant override, setpoint adjustment potentiometer,
thermometer, and a communications port are optional
features available in any combination
This manual provides general information for the
Microtech III Wall-Mounted Room Temperature
Sensors. For installation instructions refer to IM 955
Figure 36: Temperature Sensor Wiring to MicroTech III
Unit Controller (669529001)
Figure 34: MicroTech III Wall Sensor Details
.
0 to 10 K ohm
Potentiometer
Temperature
Sensor Terminals
4.59"
Status LED
(Green)
Fan Control
Slide Switch
Mode Control
Slide Switch
Tenant Override
Momentary Push Button Switch
MicroTech III Unit
Controller TB1 Terminals
Specifications
Thermistor resistance (10kΩ)
(Conforms to advance thermal products curve 2)
Ambient Temperature Limits:
Shipping and Storage: 40°F to 160°F (–40°C to 71°C)
Operating: 40°F to 140°F (4°C to 60°C)
Humidity: 5 to 95% RH, non-condensing
Locations: NEMA Type 1, Indoor only
Connections: Color Coded Leads
Wiring Sensors to the MicroTech III Unit Controller
Figure 35: Temperature Sensor Wiring to MicroTech III
Unit Controller (Kit Part No.s 669529101, 669529201)
Additional Accessories – General
Motorized Isolation Valve & Relay
The motorized valve kit is available as a factoryinstalled and wired option or may be ordered as a fieldinstalled accessory. Wired as shown in Figure 37, the motorized valve will
open on a call for compressor operation. Valves for unit
sizes 007 to 019 are 1/2" while unit sizes 024 to 060 are 3/4". Using a Normally Closed (N/C), power open valve,
wire as illustrated in figure 37.
Figure 37: Normally Closed, Power Open Motorized Valve
Actuator &
Valve Assembly
Connector
Temperature
Sensor Terminals
Anti-short
Bushing
Anti-short Bushing
Conduit
Connector
Pin(s), female
connect to terminal H8
MicroTech III Unit
Controller TB1 Terminals
Note: A special harness is provided for use with
MicroTech III controlled units. Use of a motorized
valve by others will not include the necessary wiring
harness.
IM 1049-1 / Page 27 of 36
Pump Restart Relay Kit P/N 061419001
The MicroTech III unit controller has an internal Pump
Restart Relay connected to H8, Pin 2 for the Normally
Open (N/O) terminal of the internal relay.
Figure 39: Wiring Multiple Unit Control Board (MUCP)
Multiple Unit Control Panel
Circuit Board
MicroTech III Unit Control Board
Low Voltage Terminal Strip
R
A W2 W1 Y2 Y1 G
O
C
TB2 - Unit #1
Thermostat Terminals
G Y2 W2 Y1 W1 +R -C
K3
K1
R
A W2 W1 Y2 Y1 G
O
C
TB2 - Unit #2
R
Y G W
R
TB2
Y G W
TB1
R
The output of the internal pump restart relay is 24volts AC and the output is not available when the H8
connection is used to control a motorized valve.
Y G W C
R
K2
TB4
Connect to H8, Pin 1 for the Normally Closed (N/C)
terminal of the internal relay.
Y G W
TB3
Multiple Unit Control (up to 3 units) (P/N 056794201)
The multiple unit control board is an accessory
used when up to 3-units are controlled from a single
thermostat. Typically the control panel and board is
centrally mounted between the units and thermostat. A maximum of 2 boards may be used together if up to
6-units must be connected and controlled from a single
thermostat. For detailed installation instructions refer to
IM 952.
This version of the control uses VAC relays and should
not be used in combination with any other accessories
or equipment that require VDC connections.
Figure 38: Multiple Unit Control Panel and Board
The multiple unit control board provides the components
necessary to protect the MicroTech III unit controller
from electrical damage that may occur when using
standard off-the-shelf relays.
Do not use the unoccupied (U-terminal) feature with the
multiple unit control board.
Page 28 of 36 / IM 1049-1
R
A W2 W1 Y2 Y1 G
O
C
TB2 - Unit #3
Notes:
Dotted lines represent low voltage (Class II) wiring; a
color-coded thermostat cable is recommended.
MUCP may be mounted horizontally or vertically on
heat pump cabinet or any convenient surface.
Do not use if using night setback.
Thermostat must be A.C. voltage.
Troubleshooting
The in and outs of R-410A
R-410A is a non-ozone depleting blend of two
refrigerants - HFC-125 and HFC-32 in a fifty percent
mixture. R-410A exhibits higher operating pressure and
refrigeration capacity than R-22. R-410A is intended
for use in new air conditioning applications that have
traditionally been used HCFC-22 (R-22). Due to higher
capacity and pressure of R-410A, it must not be used in
existing R-22 systems.
Although R-410A is non-flammable at ambient
temperature and atmospheric pressure, it can become
combustible under pressure when mixed with air.
Note: R-410A should not be mixed with air under
pressure for leak testing. Pressure mixtures of dry
nitrogen and R-410A can be used for leak testing.
Lubrication
R-410A should be used only with polyester (POE)
oil. The HFC refrigerant components in R-410A will
not be compatible with mineral oil or alkylbenzene
lubricants. R-410A systems will be charged with the
OEM recommended lubricant, ready for use with R410A.
Charging
Due to the zeotropic nature of R-­410A, it should
be charged as a liquid. In situations where vapor is
normally charged into a system, a valve should be
installed in the charging line to flash the liquid to vapor
while charging.
­ ake certain that the recycle or recovery equipment
M
used is designed for R-410A. The pressure of R-410A
refrigerant is approximately 60 percent greater than
that of R-22. Pressure gauges require a range up to
800 PSIG high side and 250 PSIG low side. Recovery
cylinders require a 400 PSIG rating – do not put R410A in a 300 PSIG rated cylinder.
WARNING
Recycle/recovery equipment must be designated for R410A. R-410A pressure is greater than R-22. Improper
equipment can cause severe injury or death.
Note: Because a water source heat pump operates
under a wide range of water and air temperatures, the
values printed below are to be taken as suggested
pressure and temperatures.) All McQuay water
source heat pumps are designed for commercial
use. The units are designed for the cooling
mode of operation and fail safe to cooling. The
reversing valve is energized for the heating mode of
operation.
Superheat
Head Pressure
Water Delta T
8 to 14 degrees
335-355 PSIG
10° to 14°
All information above is based on ISO standard
13256-1 and tested at these conditions.
General Maintenance
1. Normal maintenance on all units is generally
limited to filter changes. Units are provided with
permanently lubricated motors and require no oiling
even though oil caps may be provided.
2. Filter changes are required at regular intervals. The
time period between changes will depend upon
the project requirements. Some applications such
as motels produce a lot of lint from carpeting and
linen changes, and will require more frequent filter
changes. Check filters at 60-day intervals for the
first year until experience is acquired. If light cannot
be seen through the filter when held up to sunlight
or a bright light, it should be changed. A more
critical standard may be desirable.
3. The condensate drain pan should be checked
annually and cleaned and flushed as required.
4. Record performance measurements of volts, amps,
and water temperature differences (both heating and
cooling). A comparison of logged data with start-up
and other annual data is useful as an indicator of
general equipment condition.
5. Periodic lockouts almost always are caused by air or
water problems. The lockout (shutdown) of the unit
is a normal protective result. Check for dirt in the
water system, water flow rates, water temperatures,
airflow rates (may be a dirty filter), and air
temperatures. If the lockout occurs in the morning
following a return from night setback, entering air
below machine limits may be the cause.
IM 1049-1 / Page 29 of 36
Table 10: Troubleshooting Refrigeration Circuit
Air
Water
Head
Suction Compressor Super
Temp
(loops) Temp
Symptom
Subcooling
Pressure Pressure Amp Draw
Heat
Differential Differential
Charge
Undercharge System
(Possible Leak)
Low
Low
Low
High
Overcharge System
High
High
High
Normal
Low Air Flow Heating
High
High
Low Air Flow Cooling
Low
Low
Low
Low
Low Water Flow Heating
Normal
Normal
Low
Low
Normal
High Low
Safety
Lock
Out
Low
Low Pressure
Normal
High Pressure
High
High
Normal
Low
Low
Normal
Low
High
Low
High Pressure
High
High
Low
Low Temp
Low
Low
High
Low
High
Low Temp
Low Water Flow Cooling
High
High
High
High
Low
Low
High
High Pressure
High Air Flow Heating
Low
Low
Low
Low
High
Low
Low
Low Temp
High Air Flow Cooling
Low
High
Normal
High
Low
Low
Normal
High Pressure
High Water Flow Heating
Normal
Low
Normal
High
Normal
Normal
Low
High Pressure
High Water Flow Cooling
Low
Low
Low
High
Normal
Low
Low Temp
TXV Restricted
High
High
High
Low
Low
Page 30 of 36 / IM 1049-1
Low
Normal
Low
Low
Typical Refrigeration Cycles
Figure 40: Cooling Mode – (Single Circuit Only Shown)
Return Air
Thermal
Expansion Valve
Co-Axial Heat
Exchanger
Water In
Coil – Air to Refrigerant
Heat Exchanger
Water Out
Sensing Bulb and
Capillary Tube
Compressor
Blower
Reversing Valve
Conditioned Air – (Cooling)
Cooling Refrigeration Cycle
When the wall thermostat is calling for COOLING, the reversing valve directs the flow of the refrigerant, a hot gas, leaving the compressor to the water-to-refrigerant heat exchanger. Here the heat is removed by the water and the hot gas condenses to become
a liquid. The liquid then flows through a thermal expansion metering system to the air-to-refrigerant heat exchanger coil. The liquid
then evaporates becoming a gas, at the same time absorbing heat and cooling the air passing over the surfaces of the coil. The
refrigerant then flows as a low pressure gas through the reversing valve and back to the suction side of the compressor to complete
the cycle.
Figure 41: Heating Mode – (Single Circuit Only Shown)
Return Air
Thermal
Expansion Valve
Co-Axial Heat
Exchanger
Water In
Coil – Air to Refrigerant
Heat Exchanger
Water Out
Sensing Bulb
and Capillary Tube
Compressor
Blower
Reversing Valve
Conditioned Air – (Heating)
Heating Refrigeration Cycle
When the wall thermostat is calling for HEATING, the reversing valve directs the flow of the refrigerant, a hot gas, leaving the
compressor to the air-to-refrigerant heat exchanger coil. Here the heat is removed by the air passing over the surfaces of the coil
and the hot gas condenses to become a liquid. The liquid then flows through a capillary thermal expansion metering system to the
water-to-refrigerant heat exchanger. The liquid then evaporates becoming a gas, at the same time absorbing heat and cooling the
water. The refrigerant then flows as a low pressure gas through the reversing valve and back to the suction side of the compressor
to complete the cycle.
Page 31 / IM 742
IM 1049-1 / Page 31 of 36
Troubleshooting the Water Source Heat Pump Unit
Figure 42: Troubleshooting Guide - Unit Operation
Low voltage, check
power supply voltage
Fuse may be blown,
circuit breaker is open
Wire may be loose or broken.
Replace or tighten wires
Check wiring - loose or
broken and check for faulty
connection
Check relays and contacts,
also capacitor and wiring
Check high pressure switch,
low pressure switch and low
temperature switch to see if
unit is cycling on the safety
Check capacitor
Neither fan, nor compressor
runs and all LED lights
are off
Compressor runs
in short cycle
Unit
Fan operates,
compressor does not
Check wiring - loose or broken
and check for bad connection
High or Low pressure lockout
A. Cool mode, check water flow
B. Heating mode, check air flow
C. Check reversing valve for
proper valve position
Check compressor overload make sure it is closed
Check to see if the reversing
valve is not hung up and is
operating correctly
Check compressor to ground, or
for internal short to ground
Check condensate overflow
switch in cool mode of
operation
Compressor winding may be
open. Check continuity with
ohm meter
Check thermostat for
proper location
Compressor attempts to
start but does not
Insufficient cooling or
heating
Check compressor wiring
for defective wiring or loose
connection
Check for defective
compressor internal windings
with ohm meter
Check thermostat for
improper location
Check for faulty compressor
capacitor
Check blower assembly for
dirt or faulty fan motor
capacity
Check for lock rotor amp
draw
Check for low refrigerant
charge
Check for proper air flow filter could be dirty
Check amp draw on blower
assembly
Check for proper water flow
and delta T (°F)
Page 32 of 36 / IM 1049-1
Unit control, check thermostat
for correct wiring or faulty
thermostat
Troubleshooting the MicroTech III
Unit Controller
Figure 43: MicroTech III Unit Controller LED Status and
Faults Troubleshooting Reference
DANGER
Read Outputs
To avoid electrical shock, personal injury or death, be
sure that field wiring complies with local and national fire,
safety, and electrical codes, and voltage to the system is
within the limits shown in the job-specific drawings and
unit electrical data plate(s).
Check Timers
Power supply to unit must be disconnected when
making field connections. To avoid electrical shock, personal injury or death, be sure to rigorously adhere to field
wiring procedures regarding proper lockout and tagout of
components.
General Use and Information
The Microtech III unit controller is provided with two
drive terminals, R(24VAC) and C(0 VAC) that can be
used by the end user to drive the thermostat inputs (G,
Y1, Y2, W1, and W2) and control inputs (U, E, and
O). Any combination of a single board drive terminal
(R or C) may be used to operate the MicroTech III unit
controller’s control or thermostat inputs. However, only
one drive terminal (R or C) can be connected to any
individual input terminal or damage may result. Some
control inputs are not accessible to the end user (for
example, HP, LP, SLTS, and COF). Typically the Microtech III unit controller’s R (24VAC)
terminal is used to drive the board’s thermostat inputs
and control inputs by connecting it to the R terminal
of an industry standard thermostat. The control outputs
of the standard thermostat are then connected to the
Microtech III unit controller thermostat inputs and
control inputs as needed. Any remaining board input(s)
may be operated by additional thermostat outputs or
remote relays (dry contacts only).
All Microtech III unit controller inputs must be operated
by dry contacts powered by the control board’s power
terminals. No solid state devices (Triacs) may be used
to operate the Microtech III unit controller inputs. No outside power source may be used to operate the
Microtech III unit controller inputs.
Yes
Brownout
No
Yes
High
Pressure
Yes
Low
Pressure
No
Start
Compressor
No
Yes
Yes
Yes
Yes
30 Second
Time Delay
Low Suct
Temp Sensor
No
Low Suct
Temp
Request for
Water Flow
No
Room Temp
Sensor Failure
No
R-W1
No
Yes
R -Y 1
No
Condensate
Overflow
Stop Compressor
Flash Green LED
Stop Compressor
Flash Red LED
Stop Compressor
Flash Yellow LED
Flash Green LED
Solid Red LED
Stop Compressor
Heating Mode
No
Yes
Flash Yellow LED
Run in Cooling
Mode for 1 Min.
Cooling Mode
No
Yes
Turn on
Yellow LED
Stop Compressor
Reversing
Valve On
Time Delay
IM 1049-1 / Page 33 of 36
McQuay Training and Development
Now that you have made an investment in modern, efficient McQuay equipment, its care 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.
Warranty
All McQuay equipment is sold pursuant to its standard terms and conditions of sale, including Limited
Product Warranty. Consult your local McQuay Representative for warranty details. Refer to Form
933-43285Y. To find your local McQuay Representative, go to www.mcquay.com.
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.
Products Manufactured in an ISO Certified Facility.
©2010 McQuay International • www.mcquay.com • 800.432.1342
IM 1049-1 Page 36 of 36 (Rev 3-10)