Fault/malfunction Symptom
Display
Check
E1 Fan
defective
E1
Fan pcb defective
Fan not running
Control
pcb
defective
Filter
clogged
Valves/grilles
clogged
Heat exchanger clogged
Fan
soiled
No or insufficient
exhaust air; bathroom
or shower remains
damp for too long
Fan running
Ducts
clogged
E1/E2
Impeller binding or is
broken
Bearings
defective
Air intake or air
exhaust fan
Fan running too fast. No
or insufficient intake /
exhaust air
Bypass flap jammed
Bypass
Bypass motor defective
Scraping noise
Siphon does not close
Whistling noise
Air leaks at unit or duct
system
Valves/grilles not open
sufficiently
Valves/grilles
not
correctly connected to
duct
Loud noise
Air flow noise
Fan running too fast. No
or insufficient intake /
exhaust air
Siphon is empty
Drain
clogged
Condensation leak
Drain line leaking at the
collecting tray
Wiring
fault
Switch defective
Control
pcb
3-position switch has
no function
E1/E2 Fan
Interference on TV/
stereo system
EMC
filter