82
Displayed
fault code
Const.
Weath.-
comp.
System characteris-
tics
Cause
Measures
EF
X
X
Burner in a fault state Flame is lost imme-
diately after it has
build (during the
safety time).
Check gas supply (gas
pressure and gas flow
switch).
Check balanced flue sys-
tem for flue gas recircula-
tion.
Check ionisation elec-
trode (replace if required):
■
Distance to burner
gauze assembly (see
page 31)
■
Electrode contaminated
Press reset button
R
.
F0
X
X
Burner blocked
Internal fault
Replace control unit.
F1
X
X
Burner in a fault state Flue gas tempera-
ture limiter has re-
sponded.
Check heating system fill
level. Vent the system.
Press reset button
R
after
flue system has cooled
down.
F2
X
X
Burner in a fault state Temperature limiter
has responded.
Check heating system fill
level. Check circulation
pump. Vent the system.
Check temperature limiter
and connecting cables.
Press reset button
R
.
F3
X
X
Burner in a fault state Flame signal is al-
ready present at
burner start.
Check ionisation elec-
trode and connecting ca-
ble.
Press reset button
R
.
F8
X
X
Burner in a fault state Fuel valve closes
too late.
Check gas train. Check
both control paths.
Press reset button
R
.
F9
X
X
Burner in a fault state Fan speed too low
during burner start
Check fan, fan connecting
cables and power supply;
check fan control.
Press reset button
R
.
FA
X
X
Burner in a fault state Fan not in idle
state
Check fan, fan connecting
cables and fan control.
Press reset button
R
.
FC
X
X
Burner in a fault state Gas train faulty,
faulty modulation
valve control or
flue gas path
blocked
Check gas train. Check
flue system.
Press reset button
R
.
Fd
X
X
Burner in a fault state
and fault message b7
is displayed
Boiler coding card
missing
Insert the boiler coding
card.
Press reset button
R
.
Replace control unit if
fault persists.
Troubleshooting
Fault codes
(cont.)
5772 980 GB
Service