Viessmann B2TF Installation And Service Instructions Manual page 87

Fault messages
(cont.)
Displayed fault System characteristics
code
F.369 Burner in a fault state
F.370 Burner in a fault state
F.372 Burner in a fault state
F.373 Burner in a fault state
Cause
Flame is lost immediately
after flame formation (dur-
ing safety time)
Fuel valve or modulation
valve will not close.
Repeated flame loss dur-
ing calibration
Heat transfer too low dur-
ing calibration
Temperature limiter has
shut down.
Troubleshooting
Measures
Check gas supply (gas pressure
and gas flow switch).
Check balanced flue system for
flue gas recirculation.
Check ionisation electrode for the
following:
Clearance to burner gauze as-
■
sembly.
Contamination on electrode.
■
Reset the appliance.
Reset the appliance.
If fault occurs repeatedly, replace
fan unit.
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 solenoid
■
valve inlet and strainer on the in-
let side for contamination.
Note
To prevent water damage, detach
fan unit before removing the burn-
er. Deposits on the electrodes indi-
cate foreign bodies in the combus-
tion 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 ionisation electrode
have been replaced, also clean fan
unit, gas/air channel and Venturi
extension.
Reset the appliance.
Ensure adequate heat transfer.
■
Check circulation pump for faults,
■
scale or blockages.
Check 3-way diverter valve func-
■
tion in actuator test. Vent the sys-
tem.
Check function of flow sensor.
■
Reset the appliance.
87