Viessmann B2HF - Page 96

96
Displayed fault
code
System characteristics Cause Measures
F.373 Burner in a fault state Heat transfer too low dur-
ing calibration
Temperature limiter has
shut down.
■
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.
F.377 Burner in a fault state Post-processing ionisation
current calibration: Stabili-
sation conditions for post-
calibration not reached
Check gas type setting. If fault re-
curs, replace BCU burner control
unit (see page 109).
Reset the appliance.
F.378 Burner in a fault state Flame loss during stabili-
sation or operating phase
■
Check gas supply (gas pressure
and gas flow switch).
■
Check flue gas recirculation.
■
Check for contamination of ioni-
sation electrode and burner
gauze assembly.
Reset the appliance.
F.379 Burner in a fault state Flame signal not present
or insufficient
■
Check ionisation electrode con-
necting cable for damage and
ensure it is secure.
■
Check ionisation electrode, re-
place if necessary.
Reset the appliance.
F.380 Burner in a fault state Flame is lost immediately
after flame formation (dur-
ing safety time)
Check gas supply (gas pressure
and gas flow switch).
Check balanced flue system for
flue gas recirculation.
Check ionisation electrode, burner
gauze assembly:
■
Clearance to burner gauze as-
sembly
■
Contamination on electrode
Reset the appliance.
F.381 Burner in a fault state Flame loss during operat-
ing phase
Check gas supply (gas pressure
and gas flow switch).
Check balanced flue system for
flue gas recirculation.
Check ionisation electrode, burner
gauze assembly:
■
Clearance to burner gauze as-
sembly.
■
Contamination on electrode
Reset the appliance.
F.382 Burner in a fault state Fault counter has excee-
ded limit.
Reset the appliance. Work through
fault analysis using fault history.
F.383 Burner in a fault state Possible contamination of
gas line
■
Check gas line for contamination.
■
Check the gas supply pressure.
■
Replace gas fan if required.
Reset the appliance.
Troubleshooting
Fault messages (cont.)
5593201
Diagnosis