Dantherm Vent R6 User Manual

Vent R/C 2/4/6
User’s guide
EN
No. 971762 • rev. 2.2 • 18.09.2015
Der tages forbehold for trykfejl og ændringer
Dantherm can accept no responsibility for possible errors and changes
Irrtümer und Änderungen vorbehalten
Dantherm n’assume aucune responsabilité pour erreurs et modifications éventuelles
Table of contents:
1. GENERAL. ................................................................................................................................... 2
1.1 Control circuit board STXC2.................................................................................................. 2
1.1.1 Function switch. ............................................................................................................... 2
1.2 MMI STCU. ............................................................................................................................ 3
1.3 MMI STCU description. ......................................................................................................... 4
1.4 Flow chart (option). ................................................................................................................ 6
1.5 Communication module STIO (option). ................................................................................. 7
2. USER’S GUIDE. ........................................................................................................................... 8
2.1 Main menu. ............................................................................................................................. 8
2.2 Display set-up. ........................................................................................................................ 9
2.2.1 Language selection. .......................................................................................................... 9
2.2.2 Adjusting the display contrast. ......................................................................................... 9
2.3 Time setting. ......................................................................................................................... 10
2.4 Filter configuration. .............................................................................................................. 11
2.5 Setting of manual running mode........................................................................................... 13
2.6 Setting a week program. ....................................................................................................... 14
2.6.1 Example of setting a week program. .............................................................................. 15
2.7 Alarms................................................................................................................................... 17
2.7.1 Critical failure reset. ....................................................................................................... 19
2.8 Reading the actual conditions ............................................................................................... 21
2.9 Reading technical data. ......................................................................................................... 21
3. CONTROL STRATEGY. ........................................................................................................... 26
3.1 Ventilation. ........................................................................................................................... 26
3.1.1 Fresh air reduction at low outside temperatures. ........................................................... 26
3.1.2 Filter surveillance. .......................................................................................................... 26
3.2 Temperature control.............................................................................................................. 26
3.2.1 Heat recovery. ................................................................................................................ 27
3.2.2 Reheater coil. ................................................................................................................. 27
3.2.3 Cooling at summer nights. ............................................................................................. 27
3.3 Clean blowing function - heat wheel. ................................................................................... 29
3.4 De-icing function. ................................................................................................................. 29
3.5 Fan override. ......................................................................................................................... 29
3.5.1
HUMIDITY OVERRIDE ..................................................................................................... 29
3.6 Displacement of temperature set point. ................................................................................ 29
3.7 Extended operation. .............................................................................................................. 29
STXC2 User’s guide
Version 2.0
1.
General.
The control system is based on the following control units:





A STXC2 control circuit board that is mounted in the ventilation unit.
A STPT circuit board with a two-channel pressure sensor. It is mounted in the ventilation unit.
A STCU wall mounted MMI (Man Machine Interface).
A STLD wall mounted flow chart with LED’s (option).
A STIO circuit board for connection to a BMS (Building Management System) (option).
A single wire system (serial) communication) connects the circuit boards.
1.1
Control circuit board STXC2.
The STXC2 control circuit board and the two-channel pressure circuit board STPT2 give complete
control of air temperature and air volume by measuring and regulating the incoming signals (data).
The control of the air volume set point is displayed in m³/h, and keeps the air volume constant
independent of the duct pressures.
Regulating the amount of energy recovery by speed control of the heat wheel or, controlling the bypass damper in an air-to-air plate heat exchanger controls the temperature.
The active part of the temperature control is based on a plug connection on the ventilation unit. The
plug gives the possibility of connecting an external electric or water (LPHW) heating coil.
The ventilation system can also control a Chilled water or DX cooling coil.
There is the option of pre-cooling at night in the summer periods and reduction of ambient air
introduction in extreme cold winter periods.
1.1.1 Function switch.
The ventilation unit is equipped with a function switch that has the positions AUTO, OFF and
MAN (Manual).
AUTO
OFF
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MAN
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If the serial connection to the MMI is not present and the function switch is in position MAN, the
ventilation unit is controlled by the following factory settings on the control circuit board STXC2:




Humidity set point:
60%.
Ambient air volume: 100% (with mixing section).
Fan set point:
Maximum air volume.
Temperature set point: 20°C (room temperature control).
The MMI is connected and the function switch is in position MAN, the ventilation unit is controlled
by the manual settings. See chapter 2.5 Setting of manual running mode.
The ventilation unit is controlled in a priority, that defines the operational mode:
1:
The function switch on the ventilation unit has the highest priority.
2: Then the communication module STIO controls the operation. See chapter 1.5 Communication
module STIO. The function switch on the ventilation unit is in position AUTO.
3: The MMI STCU controls the operation. See chapter 1.3 MMI STCU description.
By activating the push button Manual the ventilation unit is controlled by the manual settings.
By activating the push button Auto the ventilation unit is controlled by the week program.
The function switch on the ventilation unit is in position AUTO.
1.2 MMI STCU.
The separate STCU MMI is equipped with an alphanumeric display and push buttons, and can be
placed on a wall up to 50m away from the ventilation unit. The wiring must not be fitted outside the
building. The ventilation unit is simple to operate with the MMI and it is with this that the settings
for the running conditions are entered.
The primary settings for the running conditions are entered in a week program.
A six-wire plug connection connects the control circuit board STXC2 to the MMI.
If the function switch on the ventilation unit is in position AUTO the ventilation unit will not run
without the MMI or the communication module STIO connected (See chapter 1.5 Communication
module STIO (Option)).
If the serial connection to the MMI is not present and the function switch is in position MAN, the
ventilation unit is controlled by the following factory settings on the control circuit board STXC2
(See chapter 1.1.1 Function switch).
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1.3
MMI STCU description.
The MMI STCU unit is delivered in a separate cabinet ready for DIN-rail mounting on a wall. The
display texts on the MMI STCU can be selected in Danish, English or Swedish.
The MMI STCU is equipped with an alphanumeric display, a three-coloured indication LED and
eight push buttons.
Indication LED
Menu UP
Decrease value
Increase value
Menu DOWN
Manual run
Auto run
Stop unit
Menu select / Save
The three-coloured indication LED provides information quickly about the running condition:



Green: The ventilation unit is OK.
Yellow: The ventilation unit needs inspection but runs (blocked filter).
Red:
The ventilation unit is stopped due to a critical failure.
The indication LED shifts from green to yellow or red if a failure occurs on the ventilation unit. The
relevant alarm text is shown on the display (See chapter 2.7 Alarms).
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The three push buttons Manual, 0 and Auto are used to select the running mode of the ventilation
unit. The lowest line on the display indicates the actual running mode with the symbol , which
points to one of the three push buttons.
By activating Manual the ventilation unit is switched to run in manual mode, that is user defined
(See chapter 2.5 Setting of manual running mode). The ventilation unit will now run according to
the manual settings for the next 2 hours (factory setting 2 hours - maximum 24 hours) and, once this
time has elapsed it will return back to the settings in the week program.
This function is very useful if, for example, you want to start or stop the ventilation unit in
unoccupied periods, without making changes in the week program.
By activating 0 the ventilation unit stops until Auto or Manual gets activated. This function can be
useful if you want to stop the ventilation unit on short working days.
By activating Auto the ventilation unit follows a pre-defined week program, which is user defined
(See chapter 2.6 Setting a week program).
The following push buttons are used to select menu and change/save settings on the display.
By pressing  or  it is possible to pick a specified menu line. The highlighted menu line shows
the actual sub menu.
When you want to select a sub menu you have to press Enter.
To increase or decrease a set point value push the buttons + or –. Press Enter to save the corrected
set point.
Moving to a menu that is above the actual menu press  until the required menu appears.
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1.4
Flow chart (option).
A flow chart equipped with LED’s can be connected to the MMI. The flow chart indicates the actual
condition for security thermostats, fans, filters etc.
The flow chart gives an easy to read and a clear view of run and fault conditions in the ventilation
unit.
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1.5
Communication module STIO (option).
Connection of the communication module STIO via the serial communication line it enables the
operation and monitoring by the BMS. The function switch on the ventilation unit is in position
AUTO when using the communication module.
By activating the analogue and digital inputs of the STIO the control will more or less be taken from
the MMI STCU.
The analogue inputs are connected to 2-10VDC signals and the digital outputs are activated by
24Vac or 12VDC supply. Some of the analogue inputs have predefined functions as set points and
running conditions.
Every single input has it’s own enable input, that activates the specific function. Functions that not
are selected on the STIO will automatically be controlled by the MMI STCU.
The analogue and digital outputs makes external monitoring possible.
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2.
User’s guide.
2.1
Main menu.
When there has been no activity for a few minutes the display will show the following primary
menu:
Monday 12:21
Actual room temp C
Supply m3h
+20,7
02500
Actual prog no 01
The actual room temperature, supply air volume and the running program step are shown on the
display.
If the ventilation unit is equipped with damper motors (ON/OFF or modulated 0-10V) on the fresh
air duct and exhaust air duct or a humidity sensor, the status for these is also shown on the display.
By pressing Enter the display shifts to the main menu. The backlight on the display is turned on. If
no push button has been activated within 2 minutes, the STCU automatically turns back to the
primary menu and the back light is turned off.
Main menu
Monday 12:21
Adjustm. / clock
Ventilation / climate
Alarms
Technical data
The push buttons  and  shift between the sub menus.
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2.2
Display set-up.
2.2.1 Language selection.
From the main menu the sub menu Technical data is selected. The sub menu Language appears:
Main menu
Monday 12:21
Technical data
Language
English
Danish
Swedish
Selecting a language with the push buttons  and . Then press Enter and the language is selected.
2.2.2 Adjusting the display contrast.
From the main menu the sub menu Technical data is selected. The sub menu Processor appears:
Main menu
Technical data
Processor
Run time
Comm error %
STCU CpuVer
STXC CpuVer
STPT CpuVer
STHP CpuVer
STIO CpuVer
Mode
Com Retry
Monday 12:21
00023
034
017
015
011
9
00726
By pressing the push buttons - and + it is possible to adjust the display contrast. Then press Enter
and the selected display contrast is saved.
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2.3
Time setting.
From the main menu the sub menu Adjustm. / clock is selected. Select the sub menu Clock adjust:
Main menu
Monday 12:21
Adjustm. / clock
Clock adjust
Day
Time
Date
Month
Year
Monday
13:31
29
06
00
By pressing the push buttons  and  the actual data for weekday, time, date, month and year are
selected. The settings are changed by the push buttons + and –. Press Enter after inputting the
settings and the changes are saved.
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2.4
Filter configuration.
It is necessary to run the filter test program at a specific air volume (”filter check value”) to enable
& set the filter failure (dirty filter) alarm. It is only possible to get an alarm at the specific air
volume. The filter test is made by the following procedure:
1.
2.
3.
The ventilation unit is turned off. The function switch is in position OFF.
The push button 0 is activated on the MMI STCU.
Choose a maximum air volume [m³/h].
Choose an acceptable differential pressure loss for the filter(difference between clean and
dirty filter).
Dantherm Air Handling recommends a differential pressure loss of 60 Pa.
The function switch on the ventilation unit is now turned to position AUTO.
In the following example a ”filter check value” at 2500m3h is used. This is the air volume
setting used in the week program (See chapter 2.6 Setting a week program).
Main menu
Technical data
Filter configuration
Check at m3h
Accepted d/Pa
Start filtertest
Monday 12:21
02500
0060
ENTER
Use the push button  to select the data point Start filtertest and press ENTER.
The control system accelerates the fan motors up to the selected ”filter check value”.
350 seconds after the fan motors are accelerated up to their maximum speed they run for
further 50 seconds. Data for the ventilation unit is set.
Main menu
Technical data
Filter configuration
Check at m3h
Accepted d/Pa
Start filtertest
Monday 12:21
Measuring wait sec.
400
The time left for the filter test is show on the display.
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02500
0060
ENTER
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With 48 seconds remaining the control system gives a feedback about the filter test.
Main menu
Technical data
Filter configuration
Check at m3h
Accepted d/Pa
Start filtertest
Monday 12:21
Measuring wait sec.
Filter test Ok
048
02500
0060
ENTER
If the selected ”filter check value” is near the maximum air volume that the ventilation unit
can handle, the filter test will fail.
Main menu
Technical data
Filter configuration
Check at m3h
Accepted d/Pa
Start filtertest
Monday 12:21
Measuring wait sec.
Filter test failed
048
02500
0060
ENTER
If a lower air volume is accepted in the week program, the filter test can be made
another time with a lower ”filter check value”.
But if a lower air volume isn’t accepted in the week program, the ventilation unit can’t
run with automatic filter surveillance.
In the configuration menu the function automatic filter surveillance (menu point ”Auto
filter surv.”) is then going to be disabled. See service engineer’s guide for further
information.
After 400 seconds (approximately 7 minutes) the ventilation unit is ready for use.
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2.5
Setting of manual running mode.
From the main menu the sub menu Adjustm. / clock is selected. Select the sub menu Manual
override. After pressing Manual the ventilation unit will run with the following data:
Main menu
Monday 12:21
Adjustm. / clock
Manual override
Temp set point C
Ventilation m3h
Manual hours
20
02500
02
Temperature, air volume and manual-time are displayed. Settings are adjusted by pressing the push
buttons + and –.
Select the data point Manual hours for setting the running time (setting in whole hours from 1 to 24
hours) in manual. After this time has elapsed the ventilation unit reverts to the settings in the week
program.
After inputting the settings press Enter to save.
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2.6
Setting a week program.
From the main menu the sub menu Adjustm. / clock is selected. Select the sub menu Program step:
Main menu
Monday 12:21
Adjustm / clock
Program step
Program step no
Ventilation m3h
Day(s)
Time
Temp set point C
Night cooling
01
02500
Monday
08:00
20
No
Pick a specific data point with the push buttons  and .
In the data point Program step no the program step is selected (maximum 20 steps), which is going
to be changed.
Individual days can be selected such as Monday, Tuesday, Wednesday etc., workdays can be
selected (Monday to Friday), weekends can be selected (Saturday and Sunday) and a full week
(Sunday to Monday).
Time (24 hour clock), temperature and air volume are selected by the push buttons + and –.
After inputting the settings in a program step press Enter to save. The next program step can be
selected in the data point Program step no.
In any unused program steps up to 20, the data point Time has the setting --: --. The control system
will then jump to the next program step.
The data point setting Time has the default factory setting --: --.
Setting for mixing section
If the ventilation unit is equipped with damper motors in a mixing section, fresh air setting can be
chosen from 0 (closed) to 100 (fully open).
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2.6.1 Example of setting a week program.
The following shows an example of a week program including cooling at summer nights (See
chapter 3.2.3 Cooling at summer nights). For further information see chapter 2.6 Setting a week
program.
Program step no. 01 and 02:
The week program begins by turning the ventilation unit on, on workdays at 08.00 and ventilation
unit is turned off at 16.00.
The room/return temperature set point is 20C.
Program step no. 03:
The ventilation unit runs providing free cooling on summer nights on workdays, early in the
morning from 04.00.
Free cooling on summer nights:
The most suitable period to use the function free cooling on summer nights is at night or early
in the morning. A quick cooling of the room is achieved.
Program step no. 04:
The ventilation unit is turned off at the weekend.
Program step no.: 01.
Main menu
Monday 12:21
Adjustm / clock
Program step
Program step no
Ventilation m3h
Day(s)
Time
Temp set point C
Night cooling
01
02500
Workd.
08:00
20
No
Program step no.: 02.
Main menu
Monday 12:25
Adjustm / clock
Program step
Program step no
Ventilation m3h
Day(s)
Time
Temp set point C
Night cooling
02
OFF
Workd.
16:00
20
No
The room/return temperature has a default factory setting of 20C. When the ventilation unit is
turned off, the room will not be supplied with heating.
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Program step no.: 03.
Main menu
Monday 12:28
Adjustm / clock
Program step
Program step no
Ventilation m3h
Day(s)
Time
Temp set point C
Night cooling
03
OFF
Workd.
04:00
20
Yes
Program step no.: 04.
Main menu
Monday 12:35
Adjustm / clock
Program step
Program step no
Ventilation m3h
Day(s)
Time
Temp set point C
Night cooling
04
OFF
Weekend
00:01
20
No
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2.7
Alarms.
If the ventilation unit does not work properly, an alarm is shown on the display and the indication
LED shifts colour from green to yellow or red.
Monday 12:21
Alarm
Fail preheat
Actual room temp C
Supply m3h
+20,7
02500
Actual prog no 01
The indication LED lights yellow as a warning. A non-critical failure has appeared. The ventilation
unit does not stop, but only needs inspection:
- ”Filter exhaust”
- ”Filter supply”
The indication LED shifts to red. A critical failure has appeared. The ventilation unit is stopped (not
Heat wheel):
- ”Fail preheat”
- ”Fail reheat”
- ”Fire supply”
- ”Fire exhaust”
- ”Fan supply”
- ”Fan exhaust”
- ”Flow supply”
- ”Flow exhaust”
- ”Supply sensor”
- ”Return sensor”
- ”Ambient sensor”
- ”Preheat sensor”
- ”Heat wheel”
A critical failure must be manually reset so that the ventilation unit can be re-started.
If the connection to the STXC2 control circuit board is not present, the following communication
failure appears on the display:
- ”No STXC Detected”
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The indication LED is in this case switched off.
To get information about the alarms select the menu Alarms in the main menu:
Adjustm. / clock
Ventilation / climate
Alarms
Technical data
Two sub menus gives information about the actual alarms and alarms listed in a “alarm history” that
have occurred since the last power failure:
Main menu
Monday 12:21
Alarms
Actual
History
Actual alarms:
Main menu
Alarms
Actual
No failures
Monday 12:21
Main menu
Alarms
History
Power failure
15:34 02-10-00
Monday 12:21
Alarms since
last power failure:
Alarms listed in the “alarm history” disappear at power failure or if the connection between the
control circuit board STXC2 and the MMI STCU has been disconnected.
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2.7.1 Critical failure reset.
If the ventilation unit is stopped due to a critical failure, then follow these instructions:
Frost thermostat has sensed a frost condition
The frost thermostat has a manual reset. The failure is reset on the frost thermostat.
Fire thermostat has sensed a fire condition
The fire thermostat has a manual reset. The failure is reset on the fire thermostat.
Overheating thermostat - OT
The overheating thermostat mounted on the electrical heating coil and is a manual reset. The failure
is reset on the overheating thermostat.
Stopped fan motor
Switching off the mains power supply for a few minutes resets a fan failure. The mains isolator is
located on the ventilation unit.
If this doesn’t solve the problem, it is necessary for further information; this can be obtained by
opening the cover on the fan motor. Under the cover a green and a red LED indicate the fan motor
condition.
See service engineer’s guide chapter 7. Indicator lights and fault signal output for further
information.
Missing airflow
Missing airflow through the ventilation unit is reset by pressing buttons  and  at the same time
and hold for a few seconds.
Another possibility is turning the function switch on the ventilation unit in position OFF and then
turn it back to the desired position.
Temperature sensor failure
A temperature sensor failure appears due to a short circuit or a missing connection to the sensor.
The failure is corrected at the sensor connection or at the wiring.
Communication failure
On the MMI the text appears ”No STXC Detected”. This is due to a broken connection in the wiring
between the control circuit board STXC2 and the MMI STCU.
Heat wheel failure
See service engineer’s guide chapter 8. Finding errors on frequency converter for heat wheel for
further information.
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2.8
Reading the actual conditions.
From the main menu the sub menu Ventilation / climate is selected. Other sub menus appear:
Main menu
Ventilation / climate
Room conditions
Ambients
Ventilation
Monday 12:21
The sub menu Room conditions is selected:
Main menu
Ventilation / climate
Room conditions
Supply temp. C
Return temp. C
Monday 12:21
+21,2
+20,7
Here the actual values for the supply air and return air temperatures are indicated.
The sub menu Ambients is selected:
Main menu
Ventilation / climate
Ambients
Ambient temp. C
Preheat temp. C
Monday 12:21
+24,3
None
Here the actual values for the ambient air and the preheat air temperatures are indicated. If in this
case a preheat air sensor is not mounted, the display shows None.
The sub menu Ventilation is selected:
Main menu
Ventilation / climate
Ventilation
Supply air %
Supply press Pa
Supply m3h
Return air %
Return press Pa
Return m3h
Monday 12:21
025
0118
01320
027
0128
01620
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Here the actual values for the ventilation are indicated:
Supply air % / Return air %
Output voltage (control signal) to the fan motors.
0% = 0V and 100% = 10V.
Supply press Pa / Return press Pa
The measured differential pressure across the fans. The value is used for calculating the air volume.
Supply m3h / Return m3h
The air volume being produced by the fans.
2.9
Reading technical data.
In the main menu the sub menu Technical data is selected:
Main menu
Technical data
Sensor inputs
Control outputs
On/off inputs
Function switch
On/off outputs
Override set points
Filter configuration
Processor
STIO Data
Language
Monday 12:21
When the sub menu Sensor inputs is selected:
Main menu
Technical data
Sensor inputs
Supply sensor C
Return sensor C
Ambient sensor C
Preheat sensor C
Fan override %
Humidity %
Temp.displacement
Supply press Pa
Return press Pa
Monday 12:21
+21,7
+20,3
+24,3
None
000
062
-2,3
1280
1262
Here the actual values for temperatures, humidity, external fan speed override, temperature
displacement and differential pressure across the fans are indicated.
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When the sub menu Control outputs is selected:
Main menu
Technical data
Control outputs
Reheat %
Preheat %
Heat recovery %
Damper %
Supply fan %
Exhaust fan %
Extra cooling %
Analog output 1 %
Analog output 2 %
Monday 12:21
100
None
100
000
000
000
000
000
000
Here the actual values for output signals 0-100% is indicated.
When the sub menu On/off inputs is selected:
Main menu
Technical data
On/off inputs
Fail preheat
Fail reheat
Fire supply
Fire exhaust
Fan fail supply
Fan fail exhaust
Flow supply
Flow exhaust
Filter supply
Filter exhaust
Heat wheel
De-ice bypass
Monday 12:21
Alarm
Ok
Ok
Ok
Ok
Ok
Ok
Ok
Ok
Ok
Ok
Off
Here the actual status for failure inputs and de-icing the heat exchanger (De-ice bypass) are
indicated. If the ventilation unit is working correctly the status will show Ok. If a data point is in
alarm, status will show Alarm (See chapter 2.7.1 Critical failure reset).
The heat exchanger de-icing status is shown as Off (no icing up) or On (icing up).
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When the sub menu Function switch is selected:
Main menu
Technical data
Function switch
Function auto
Function low
Function high
Monday 12:21
On
Off
Off
Here the function switch position is indicated. A selected position is shown as On, the other
positions are shown as Off.
If every data point is shown as Off, the function switch is in position OFF and the ventilation unit is
stopped.
When the sub menu On/off outputs is selected:
Main menu
Technical data
On/off outputs
Supply fan
Exhaust fan
Bypass damper
Ambient damper
Lamp green
Lamp red
Lamp yellow
Monday 12:21
Off
Off
Stop
Close
On
On
Off
Here the status for the outputs is indicated.
Supply fan:
Exhaust fan:
Bypass damper:
Ambient damper:
Lamp green:
Lamp red:
Lamp yellow:
On (fan runs) and Off (fan is stopped).
On (fan runs) and Off (fan is stopped).
Open (damper opens), Close (damper closes) and
Stop (damper motor is stopped).
Open (damper opens), Close (damper closes).
On - voltage on the ventilation unit.
On - a critical failure on the ventilation unit. Off - no critical failure.
On - a filter is dirty. Off - no dirty filter.
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When the sub menu Override set points is selected:
Main menu
Technical data
Override set points
Humidity %
Min. supply
Fan override
Max air volume
Monday 12:21
63
16
10
1700
Override set points for humidity, minimum supply temperature and fan speed are selected in this
menu.
Humidity %: This menu item is only visible if “YES” is choosen in the “Humidity sensor” menu in
the controller configuration menu. For further information, please see the service
manual, section 5.
When the measured humidity rises above the set point (40 - 70%), the fan speed
increases to 100%. See chapter 3.5 Humidity override for further information.
Min. supply: The minimum supply temperature (5 - 40°C).
Fan override: The set point 0 - 100% defined by a sensor output signal 0 - 10V (0 - max.value).
When the measured input value rises above the set point, the fan speed increases to
100%. See chapter 3.6 Fan override for further information.
Max. air volume:
Key in the maximum allowed air volume at override (humidity or fan override)
When the sub menu Processor is selected:
Main menu
Technical data
Processor
Run time
Comm error %
STCU CpuVer
STXC CpuVer
STPT CpuVer
STHP CpuVer
STIO CpuVer
Mode
Com Retry
Monday 12:21
00023
034
017
015
011
9
00726
Here the data for the control system are listed.
Run time: The total running time (hours) for the ventilation unit.
Comm error % and rest of the data points: Data used by Dantherm Air Handling AS/.
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When the sub menu STIO Data is selected:
Main menu
Technical data
STIO Data
Humidity %
Fan override %
Temp set point C
Ventilation m3h
Exhaust volume
Fresh air %
Temp. Ctr. sensor
Night cooling
Auto
Manuel
Cooling
Monday 12:21
063
020
21
02500
100
R
Off
On
Off
Off
Here the data from the STIO communication module can be read.
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3.
Control strategy.
3.1
Ventilation.
When all the safety components (frost, fire and fan failures) are in ON-position and the ventilation
unit is turned ON, the fresh air damper and the exhaust air damper opens. After 30 seconds the fans
start. The fans will then run with the settings input in the control system.
3.1.1 Fresh air reduction at low outside temperatures.
The supply fan speed is reduced gradually to 2/3rds of the set point value, when the supply
temperature has reached a minimum temperature.
The function can be selected in the configuration menu.
3.1.2 Filter surveillance.
The control system has an automatic surveillance of dirty filters.
The control system accelerates the fan motors up to the selected ”filter check value”.
350 seconds after the fan motors are accelerated up to their maximum speed they run for a further
50 seconds. Data for the ventilation unit is then recorded.
When the control signal is increased by 10% (to reach the same air volume pressure) alarm for dirty
filter is given and the indication LED on the MMI STCU shifts to yellow.
3.2
Temperature control.
On the MMI STCU the desired room or supply temperature is selected between 15 and 35°C. The
control system keeps the room or supply temperature constant by controlling the reheater coil,
bypass damper (air-to-air plate heat exchanger) or speed control of the heat wheel.
The heat requirement is split into 1/100 (0-100%). The temperature P-band setting (5 to 50°C) is
made on the control circuit board STXC2 in the ventilation unit.
Close
Energy
recovery
(ERS)
Open
Extra cool (ECS)
Reheat (HTS)
0
35
40
50
55
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85
100
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3.2.1 Heat recovery.
In an air-to-air plate heat exchanger the By-pass damper takes 10% (hysteresis) of the P-band
between heating mode and cooling mode (more fresh air for cooling).
When heating is needed, the bypass damper closes by pulsing (runs slowly). When cooling is
needed, the bypass damper opens by pulsing. If the outside temperature is higher than the return air
temperature, the bypass damper will not open.
The heat wheel heat recovery works the same way as the bypass damper and takes 10% of the Pband between heating mode and cooling mode. The function is linear.
If more heat is required, the heat wheel speed increases (2-10V output signal rises). When the heat
requirement reduces, the heat-wheel speed decreases.
3.2.2 Reheater coil.
The active part of the temperature control is a plug connection on the ventilation unit, where a reheater coil can be connected (electrical heating coil or LPHW coil).
A reheater coil is controlled by a 2-10V signal.
3.2.3 Cooling at summer nights.
The function cooling at summer nights is used for cooling the room in the summer period.
The most suitable period to use the function cooling at summer nights is at night or early in the
morning before the ventilation requirement is turned on.
When the week program permit the function cooling at summer nights, the ventilation unit starts up
if there haven’t been need of heating in the last running period.
The ventilation unit starts up slowly and 3 minutes later the room/return and ambient temperature is
measured. If the following conditions for the function cooling at summer nights are present, the
ventilation unit continues to run. Else the ventilation unit stops.
Conditions for the function cooling at summer nights:
The measured room/return temperature must be higher than the temperature set point +2°C.
The measured ambient temperature must be lower than the room/return temperature -2°C.
See example on week program using the function cooling at summer nights, chapter 2.6.1 Example
of setting a week program.
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3.3
Clean blowing function - heat wheel.
The heat wheel is rotated for 1 minute every hour if there has been no rotation during one-hour (5V
control signal) to prevent a build up of particulate.
3.4
De-icing function.
If the differential pressure across the heat exchanger rises above a set point value measured by an
extra mounted pressurestat (extra), then de-icing will take place.
3.5
Fan override.
When the measured input value (0-10V the same as 0-100%) on analogue input IN1 on the control
circuit board STXC2 rises above the setpoint, the fan speed will increase so that the air volume
gradually increases to the maximum value, keyed in under the menu “Override set points” See
further information in section 2.9 Reading technical data/Override set points for setting of set points
and maximum air volume.. The display shows the text ”Fan override”.
Monday 12:21
Fan override
Actual room temp C
Supply m3h
+20,7
02500
Actual prog no 01
3.5.1 Override humidity.
The fresh air damper and the exhaust air damper (modulating damper motors) in a mixing section
are overridden to open 100% if the measured humidity is between the setpoint and 10% above the
setpoint. If the humidity rises further, the fan speed increases gradually to set max value.
When the humidity has fallen beneath the setpoint, the fans run for further 10 minutes at the actual
speed.
A ventilation unit equipped with ON/OFF damper motors, only the fan speed increases to 100%,
when the measured humidity is 10% above the setpoint.
At an outdoor temperature in the range from +10 to -10°C the humidity setpoint is gradually
reduced to 10%. Settings see chapter 2.9 Reading technical data / Override set points.
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3.6
Displacement of temperature set point.
By providing an input signal (2-10V) to analogue input IN2 on the control circuit board STXC2, the
temperature displacement +/-5°C, related to the setpoint, is enabled.
If the temperature input is left open (no connection) the displacement is disabled.
The temperature displacement is shown on the following graph:
Input signal
10V
6V
2V
Temp. setpoint
Setpoint-5K
3.7
Setpoint
neutral
Setpoint+5K
Extended operation.
By selecting the function switch on the ventilation unit to position AUTO it is possible to override
the ventilation unit so it runs with the manual settings from the MMI STCU.
By adding a short (maximum 3 seconds) voltfree starting signal, the ventilation unit runs in the time
defined in the MMI STCU in the data point Manuel hours (See chapter 2.5 Setting of manual
running mode).
By adding a longer starting signal, the ventilation unit runs as long as the starting signal is present.
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