Viessmann VITODENS 222-F Installation And Service Instructions Manual page 86

Troubleshooting
Fault messages
(cont.)
Fault number System characteristics
on the display
F.464 Burner in a fault state
F.467 Burner in a fault state
86
Cause
Ionisation current too low
during calibration. Differ-
ence compared to previ-
ous value not plausible.
Gas supply insufficient
during calibration
Measures
Check ionisation electrode and
connecting cable. Check plug-in
connections for loose contacts.
Check whether there is a lot of
dust in the ventilation air (e.g. from
construction work).
Check flue system; remove flue
gas recirculation if required.
Check system for condensate
backup.
Note
To prevent water damage, detach
fan unit before removing the burn-
er.
Replace burner control unit if fault
is permanent.
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.
Test static gas pressure and gas
flow pressure.
Check that on-site gas line and gas
flow switch are correctly sized.
Visually inspect gas train inlet and
strainer on the inlet side for con-
tamination.
Note
Contamination from a brazed gas
line, for example, can block up the
gas train strainer on the inlet side.
Reset the appliance.