40
Displayed fault
code
System characteristics
Cause
Measures
F F4
Flame does not build during
the safety time, no signal re-
ported by the ionisation flame
monitor.
Incorrect gas type selec-
ted
Adjust gas type (see page 10).
F F4
Flame does not build during
the safety time, no signal re-
ported by the ionisation flame
monitor.
Gas train does not open.
Check connecting cable. Check
the gas train and replace if re-
quired.
F F4
Flame does not build during
the safety time, no signal re-
ported by the ionisation flame
monitor.
Combustion characteris-
tics not ideal
Adjust burner setting. If necessary
also adjust the setting screws
when the burner is off to facilitate
the burner start.
F F5
Air pressure switch 1 reports
no air pressure, fan not run-
ning.
Air pressure switch 1 faul-
ty, incorrectly connected
or incorrectly set
Replace air pressure switch 1, con-
nect or adjust correctly.
F F5
Air pressure switch 1
switches off during operation
Flue gas back pressure,
condensate banked up, air
pressure switch 1 hose
faulty, connecting hose
leaking
Remove flue gas back pressure.
Check for backed up condensate.
Reset the burner control unit. Re-
place hose.
F F6
Gas pressure switch reports
no gas pressure.
Gas shut-off valve closed;
gas pressure switch faulty;
multiple problems with gas
supply
Open the gas shut-off valve. Check
gas flow pressure. Replace gas fil-
ter if required. Reset the burner
control unit. Replace gas train.
F F7
Fan pressure is created dur-
ing the idle state check of air
pressure switch 1.
Wind influence on fan
Check the flue draught (chimney).
F F7
Contact of air pressure switch
1 not in idle state
Air pressure switch 1 faul-
ty
Replace air pressure switch 1.
F F8
Flame tears off during opera-
tion.
Incorrect gas type selec-
ted
Adjust gas type (see page 10).
F F8
Flame tears off during opera-
tion.
Burner gauze assembly
faulty
Check the burner gauze assembly.
Replace the burner gauze assem-
bly if it is damaged.
F F8
Flame tears off during opera-
tion.
Combustion characteris-
tics not ideal
Adjust burner (see from page 16).
F F8
Flame tears off during modu-
lation (burner output increa-
ses).
Combustion characteris-
tics not ideal
Air pressure switch adjus-
ted incorrectly.
Adjust burner (see page 16).
Adjust air pressure switch (see
page 57).
F F9
Fan not running; fan speed
not reached.
Fan faulty; cables are faul-
ty or broken
Check cables. Replace fan if re-
quired.
F F9
Status duration too long, fan
ramp-up
Internal fault; fan cannot
reach its set value.
Replace fan or burner control unit.
F F9
Fan speed deviation
Fan faulty, cable "
a-Ö
A"
faulty or broken
Check cable. Replace cable
"
a-Ö
A" or fan if necessary.
Troubleshooting
Fault codes
(cont.)
5816717
Diagnosis