63
Displayed fault
code
System characteristics
Cause
Measures
352
Burner in a fault state
Combustion CO limit ex-
ceeded
Check entire flue gas path for the
following:
■
Leaks
■
Flue gas back pressure caused
by water pocket (if flue system
fall is insufficient)
■
Constrictions
■
Blockages
Repair flue system if necessary.
Reset the appliance.
353
Shutdown with restart if de-
mand exists
Insufficient gas supply,
burner output reduced
Check the gas supply.
Visually inspect gas solenoid valve
inlet strainer for contamination.
Reset the appliance.
354
Burner in a fault state
Gas modulation valve tol-
erance outside permissi-
ble range
Replace gas fan unit.
355
Burner in a fault state
Analogue signal reference
check: Flame signal is al-
ready present at burner
start.
Replace the HBMU heat manage-
ment unit. See chapter "Replacing
the HBMU heat management unit".
359
Burner in a fault state
No ignition spark
■
Check whether the ignition elec-
trode insulation is damaged.
■
Check for a voltage of 230 V
∼
at
the ignition module during the ig-
nition phase. If not, replace the
HBMU heat management unit.
■
If 230 V~ is present at the igni-
tion module but there is still a
fault, replace the ignition module.
■
Check connecting cables and
leads from ignition module and
ignition electrode.
Reset the appliance.
361
Burner in a fault state
Flame signal is not
present or insufficient at
burner start.
Check ionisation electrode and
connecting cable. Check plug-in
connections for loose contacts.
Note
Deposits on the electrodes indicate
foreign bodies in the combustion
air. Check the installation room and
flue system for causes of the de-
posits. For example: Laundry de-
tergents, cleaning agents, toilet-
ries, deposits in the ventilation air
supply (chimney)
Reset the appliance.
364
Burner in a fault state
Internal fault.
Replace the HBMU heat manage-
ment unit.
365
Burner in a fault state
Gas valve relay contact
feedback implausible (re-
lay contact is "welded up")
Replace the HBMU heat manage-
ment unit.
Troubleshooting
Fault messages
(cont.)
6179762
Diagnosis
