Fault rectification

Fault finding and repairs only permissible when carried out by qualified electricians.

Danger to life from electric shock.

  1. Prior to accessing the connection terminals, switch off all supply circuits. Switch off mains fuse, secure against being accidentally switched back on and position a visible warning sign.

 

Fault

Cause → Measure

Fan performance inadequate.

Dirty filter. → Replace filter.

Locking hook not engaged. → Engage fan insert correctly.

Incorrect duct diameter. → Check diameter of the main duct.

Supply air cross section is too small. → Increase the supply air cross section.

VZ, F and H models: No fan overrun.

 

The external conductor L connected to terminal 1 is interrupted when the unit is switched off. → Connect unit as per wiring diagram.

VZ models: Unit starts up immediately and stops immediately if is switched off.

Terminals 1 and 3 are reversed. → Connect unit as per wiring diagram.

 

Fan is too loud.

Dirty filter. → Replace filter.

Fan insert incorrectly installed. → Insert fan insert correctly in accordance with these instructions.

The main duct is undersized. → Re-calculate pressure losses.

H model does not switch from base load to full load operation despite there being humidity in the room.

No rapid increase in humidity (7 % in 2 minutes) took place.

H model no longer switches back to base load operation or off even after a long period in full load operation.

The level has not yet fallen below reference value. After 1 h, the valve automatically switches from full load operation to base load operation after an overrun time of 15 minutes and resets the reference value.

Additional consumers connected to terminal 4.

Damage to the unit if connected incorrectly.

Do not connect additional consumers to terminal 4.

The unit may only be connected according to the wiring diagrams (Wiring diagrams).

If the fault persists or reoccurs: Disconnect the unit completely from the power supply. Let a qualified electrician determine the cause of the fault and eliminate it. If you have any question relating to troubleshooting: Service: +49 7720 6940.