Viessmann VITODENS 222-F Installation And Service Instructions Manual page 76

Troubleshooting
Fault messages
(cont.)
Fault number System characteristics
on the display
F.346 Burner in a fault state
F.348 Burner in a fault state
F.349 Control mode
Burner is operating with a
limited modulation range.
F.350 Burner in a fault state
F.351 Burner in a fault state
F.352 Burner in a fault state
F.353 Burner locked out
F.354 Burner in a fault state
76
Cause
Ionisation current calibra-
tion error
Gas modulation valve
Air mass rate flow not de-
tected correctly in fan unit.
Ionisation voltage lies out-
side the permissible range
Ionisation current lies out-
side the permissible range
CO limit within appliance
exceeded.
Insufficient gas supply,
burner output reduced.
Gas modulation valve tol-
erance outside permissi-
ble range
Measures
Check the gas supply pressure.
■
Check gas train strainer on the
inlet side for contamination.
Check ionisation electrode for
■
contamination.
Check gap between ionisation
electrode and burner gauze as-
sembly (see page 43).
Reset the appliance.
Check flue system; remove flue
■
gas recirculation if required.
Check the connecting cable to
■
the fan unit.
Check impeller for ease of opera-
■
tion.
Reset the appliance.
Check connecting cables to the
gas train for damage.
Check the flue system for flue gas
back pressure.
Check gas train.
Reset the appliance.
Check mass flow sensor on the fan
unit. Check the flue system for flue
gas back pressure.
Check ionisation electrode and
connecting cable.
Reset the appliance.
Check ionisation electrode and
connecting cable.
Reset the appliance.
Check entire flue gas path for the
following:
Flue gas recirculation
■
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.
Check the gas supply.
Optically check input-side screen
in the gas train for contamination.
Reset the appliance.
Check connecting cables to the
gas train for damage.
Check gas train.
Check the flue system for block-
ages or constrictions.
Reset the appliance.