Viessmann VITODENS 222-F Installation And Service Instructions Manual page 81

Fault messages
(cont.)
Fault number System characteristics
on the display
F.377 Burner in a fault state
F.378 Burner in a fault state
Cause
Post-processing ionisation
current calibration: Stabili-
sation conditions for post-
calibration not reached
Flame loss during stabili-
sation or operating phase
Troubleshooting
Measures
Check ionisation electrode and
connecting cable. Check plug-in
connections for loose contacts.
Check flue system; remove flue
gas recirculation if required.
Check system for condensate
backup.
Visually inspect gas train inlet and
strainer on the inlet side for con-
tamination.
Note
To prevent water damage, detach
fan unit before removing the burn-
er.
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).
If burner gauze assembly and ioni-
sation electrode have been re-
placed, also clean fan unit, gas/air
channel and Venturi extension.
Reset the appliance.
Check gas supply (gas pressure
■
and gas flow switch).
Check gas train.
■
Check system for condensate
■
backup.
Note
To prevent water damage, de-
tach fan unit before removing the
burner.
Check ionisation electrode and
■
connecting cable.
Check ignition:
Connecting cables to ignition
■
module and ignition electrode
Ignition electrode clearance and
■
contamination.
Check ignition electrode for bro-
■
ken ceramic.
Reset the appliance.
81