Viessmann B0KA - Page 67

67
Displayed fault
code
System characteristics Cause Measures
377 Burner in a fault state Post-processing of ionisa-
tion current calibration:
Stabilisation conditions for
post-calibration not met
Check gas type setting. If the fault
occurs repeatedly, replace the
HBMU heat management unit. See
chapter "Replacing the HBMU heat
management unit".
Reset the appliance.
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.
379 Burner in a fault state Flame signal not present
or insufficient
■
Check ionisation electrode con-
necting cable for damage and
firm seating.
■
Check ionisation electrode. Re-
place if necessary.
Reset the appliance.
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 and
burner gauze assembly:
■
Clearance to burner gauze as-
sembly
■
Contamination on electrode
Reset the appliance.
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 and
burner gauze assembly:
■
Clearance to burner gauze as-
sembly
■
Contamination on electrode
Reset the appliance.
382 Burner in a fault state Fault counter has excee-
ded limit.
Reset the appliance. Work through
fault analysis using fault history.
383, 384 Burner in a fault state Possible contamination of
gas line
■
Check gas line for contamination.
■
Check the gas supply pressure.
■
Replace gas fan if necessary.
Reset the appliance.
385 Burner in a fault state Short circuit, signal 1, ioni-
sation current
HBMU heat management
unit faulty
Check IO electrode for earth fault.
If the fault persists, replace the
HBMU heat management unit.
Reset the appliance.
Troubleshooting
Fault messages (cont.)
6179762
Diagnosis