14
2. The unit could be in defrost mode. This reduces the fan speed and in some cases shuts down the supply air fan com-
pletely during the defrosting cycle. The fans go back to normal after defrosting. There should be a defrosting function
icon visible on the home screen if defrosting is active.
3. Speed of fans is linearly reduced when the outdoor air temperature is below 0°C and an outdoor airflow compensa-
tion function is enabled.
4. Check if temporary user mode that reduces airflow is not activated, for example
Away
,
Holiday
, etc. Also check dig-
ital inputs
Central Vacuum Cleaner
and
Cooker Hood
.
5. Check the airflow settings in the control panel.
6. Check week schedule settings (chapter 3.2.8).
7. Check filters. Is change of filters required?
8. Check diffusers/louvres. Is cleaning of diffusers/louvres required?
9. Check fans and heat exchange block. Is cleaning required?
10.Check if the buildings air intake and roof unit (exhaust) have been clogged.
11.Check visible duct runs for damage and/or build up of dust/pollution.
12.Check diffuser/louvre openings.
The unit cannot be controlled (control functions are stuck
1. Reset control functions by disconnecting mains power for at least 10 seconds.
2. Check the modular contact connection between the control panel and the main printed circuit board.
Low supply air temperature
1. Check the control panel for alarms.
2. Check the active user functions on the control panel if defrosting function is running.
3. Check set supply air temperature on the control panel.
4. Check if
ECO
mode is activated on the control panel (it is a power saving function and prevents the heater from
activating).
5. Check if user modes
Holiday
,
Away
or
Crowded
are activated on the control panel or via a hardwired switch.
6. Check the analogue inputs in the service menu to verify that the temperature sensors are functioning correctly.
7. In case of installed electrical/other re-heater battery: Check if the overheat protection thermostat is still active. If
necessary, reset by pressing the red button on the front plate of the electrical re-heater.
8. Check if the extract filter must be changed.
9. Check if the unit has a re-heater battery connected. At very cold outdoor conditions an electrical or water heating
battery might be necessary. A re-heater battery can be acquired as an accessory.
Noise/vibrations
1. Clean fan impellers.
2. Check that the screws holding the fans are tightened.
3. Check that the anti vibration lists are fitted to the mounting bracket and to the back of the unit.
6
Electrical data
Model
Fans (W )
Heater (W)
Total (W)
Fuse (mains) (A)
VTC 300
170
–
170
10
VTC 300 with reheater
170
1700
1870
10
Voltage 230V 1~, 50Hz
254297 | v01
