77
Fault number
on the display
System characteristics
Cause
Measures
F.355
Burner in a fault state
Analogue signal reference
check: Flame signal is al-
ready present at burner
start.
Check system for condensate
backup.
Note
To prevent water damage, detach
fan unit before removing the burn-
er.
Reset the appliance.
F.357
Burner in a fault state
Insufficient gas supply
Check that the gas shut-off valve is
open.
Optically check input-side screen
in the gas train for contamination.
Test static gas pressure and gas
flow pressure. Check that on-site
gas line and gas flow switch are
correctly sized.
Note
If the building pressure regulator
has a leak, you may notice rising
pressure when the burner is idle.
When the system is restarted, the
gas flow switch may trip.
Reset the appliance.
F.359
Burner in a fault state
No ignition spark
Check connection cables and
leads from ignition module and ig-
nition electrode.
Check for a voltage of 230 V~ at
the ignition module during the igni-
tion phase
Check whether the ignition elec-
trode insulation is damaged.
Reset the appliance.
F.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.
F.365
Burner in a fault state
Relay contact gas valve
feedback implausible
Reset the appliance.
F.366
Burner in a fault state
Gas valve electricity sup-
ply does not turn off.
Reset the appliance.
Troubleshooting
Fault messages
(cont.)
6130884
Service
