39
Displayed fault
code
System characteristics
Cause
Measures
F B7
Burner control unit in a fault
state; system cooling down;
burner control unit locked out.
Coding card not inserted
in the burner control unit;
incorrect or faulty coding
card
Insert coding card. Check coding
card. Replace if necessary.
F B7
Type of coding card
Coding card does not
match burner control unit.
Replace coding card or burner
control unit.
Danger
Plug-in terminals on the
burner control unit are live.
Only replace the coding card
when the burner control unit
has been isolated from the
power supply.
F E4
Burner shuts down.
Multiple detection of un-
dervoltage with recurrence
and renewed undervolt-
age
Check the power supply.
F E5
Burner control unit in a fault
state
Internal fault of the burner
control unit and during test
of ionisation input
Replace burner control unit.
F EE
Burner control unit in a fault
state
Internal error in feedback
from gas safety valves.
The output relay does not
respond.
Reset or replace burner control
unit.
F EF
Burner control unit in a fault
state
Internal error in feedback
from gas safety valves.
The output relay does not
respond.
Reset or replace burner control
unit.
F F3
Ionisation flame monitor re-
ports faulty flame signal dur-
ing start-up or after the post-
purge.
Ionisation electrode or burner
gauze assembly damaged.
Gas train leaks (gas is es-
caping and burning). In-
correct coding card.
Check ionisation path. Check ioni-
sation electrode for earth fault.
Check burner gauze assembly for
deformation.
Replace coding card. Replace gas
train.
F F4
No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
Ionisation electrode incor-
rectly adjusted, ionisation
electrode not plugged in.
Earth fault of electrode or
cable
Insert plug of ionisation electrode;
check cable; adjust ionisation elec-
trode (see page 24).
F F4
No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
Ignition electrodes incor-
rectly adjusted, electrode
earth fault, ignition unit
faulty, burner control unit
faulty
Adjust ignition electrodes (see
page 24); replace ignition unit. Re-
place burner control unit.
F F4
No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
Insulation body of ignition
or ionisation electrode
cracked
Replace ignition or ionisation elec-
trode.
F F4
Poor start-up characteristics
(start enrichment). Solenoid
valve not switching.
Compensation lines not
connected, solenoid valve
faulty, output relay of
burner control unit faulty
Check compensation lines and
connections, replace compensa-
tion lines. Replace the solenoid
valve. Replace burner control unit.
Troubleshooting
Fault codes
(cont.)
5816717
Diagnosis
