16 Spare parts
22
Fault
Cause → Measure
Fan performance inad-
equate.
Dirty filter. → Replace
filter.
Locking hook not en-
gaged. → 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 dia-
gram.
Fan is too loud.
Dirty filter. → Replace
filter.
Fan insert incorrectly in-
stalled. → Insert fan in-
sert correctly in accord-
ance with these instruc-
tions.
The main duct is under-
sized. → Re-calculate
pressure losses.
H model does not
switch from base load
to full load operation
despite there being hu-
midity in the room.
No rapid increase in hu-
midity (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 over-
run time of 15 minutes
and resets the refer-
ence value.
Fault
Cause → Measure
Additional consumers
connected to terminal 4.
Damage to the unit if
connected incorrectly.
Do not connect addi-
tional consumers to ter-
minal 4.
The unit may only be
connected according to
the 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 re-
lating to troubleshooting: Service: +49 7720 6940.
16 Spare parts
Spare parts may only be sourced from and
fitted by a specialist installer.
