
47
Fault
code
*1
Display
System charac-
teristics
Cause
Measure
F 40
None
Burner control unit
in fault state
Set default value
for fan in parame-
ter set incorrect
Replace memory
stick
I
Danger
Plug-in termi-
nals on the
burner control
unit 'live'.
Only replace
stick when the
power has
been isolated
from the
burner control
unit
F 41
F 41
Varying fan speed Fan faulty; cable
"100A" faulty or
broken; fan
unsuitable for the
required speed
Check cable and
replace cable
"100A" or fan if
required
F 42
F 42
No fan feedback
Fan faulty; exter-
nal power supply
to fan not connec-
ted or faulty; cable
"100A" faulty or
broken; fan
blocked (poss. by
a foreign body)
Check cable
"100A"; check
external power
supply; replace
cable or fan;
remove foreign
bodies
F 43
F 43
Burner control unit
in fault state
Internal fault of the
burner control unit
and during test of
ionisation input
Replace burner
control unit
F 50
F 50
Burner control unit
in fault state
Internal fault in
servomotor feed-
back; output relay
does not respond
Replace burner
control unit
*1
All fault codes are saved to the fault memory and the last 10 can be called up.
Troubleshooting
Diagnosis
(cont.)
5692 908 GB