Viessmann Vitodens 050-W Installation And Service Instructions Manual page 70

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
458 Burner in a fault state
461 Burner in a fault state
462 Burner in a fault state
463 Burner in a fault state
70
Cause
Incorrect reset sequence.
Flue gas damper fault.
Feedback input of the ex-
ternal gas safety valve
causes the burner start to
be aborted.
Contaminated combustion
air, flue gas recirculation
Measures
Check connections between
HBMU heat management unit and
HMI programming unit.
Reset the appliance.
Check flue gas damper.
Check safety valve and connec-
tion.
Check flue system for contamina-
tion and flue gas recirculation.
Clean flue system if necessary.
Reset the burner.
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.