Viessmann B1KE Combi Series Installation And Service Instructions Manual page 78

Troubleshooting
Fault Messages
Displayed System characteristics
fault code
F.377 Burner in a fault state
F.378 Burner in a fault state
F.379 Burner in a fault state
F.380 Burner in a fault state
F.381 Burner in a fault state
F.382 Burner in a fault state
F.383, Burner in a fault state
F.384
F.385 Burner in a fault state
F.386 Burner in a fault state
F.387 Burner in a fault state
F.388 Burner in a fault state
78
(continued)
Cause
Post-processing of
ionization adjustment:
Stabilization conditions
for post calibration
not met
Flame loss during
stabilization or
operating phase
Flame signal not
present or insufficient
Flame loss
immediately after
flame formation
(during safety time)
Flame loss during
operating phase
Error counter has
exceeded limit.
Possible contamination
of gas line
Short circuit, signal
1, ionization current.
BCU burner control
unit faulty.
BCU burner control
unit faulty
Ground fault,
ionization current.
BCU burner control
unit faulty.
BCU burner control
unit faulty
Vitodens 100-W, B1HE/B1KE Combi Installation/Service
Measures
Check gas type setting. If fault recurs, replace BCU
burner control unit: See page 89.
Reset the boiler.
Check gas supply (gas pressure and gas flow switch).

Check flue gas recirculation.

Check for contamination of ionization electrode and

flame body assembly.
Reset the boiler.
Check ionization electrode connecting cable for

damage and firm seating.
Check ionization electrode; replace if necessary.

Reset the boiler.
Check gas supply (gas pressure and gas flow switch).
Check balanced flue system for flue gas recirculation.
Check ionization electrode and flame body assembly:
Clearance to flame body assembly

Contamination on electrode

Reset the boiler.
Check gas supply (gas pressure and gas flow switch).
Check balanced flue system for flue gas recirculation.
Check ionization electrode and flame body assembly:
Clearance to flame body assembly.

Contamination on electrode

Reset the boiler.
Reset the boiler.
Work through fault analysis using fault history.
Check gas line for contamination.

Check the gas supply pressure.

Replace gas fan if necessary.

Reset the boiler.
Check ionization electrode and connecting cable.
If fault persists, replace BCU burner control unit:
See page 89.
Reset the boiler.
Replace BCU burner control unit:
See page 89.
Reset the boiler.
1. Check system for condensate backup.
Check the condensate drain and siphon trap.

Replace insulation blocks, electrodes and flame

body assembly if necessary.
Note: To prevent water damage, detach fan unit
before removing the burner. Protect electronic
components from escaping condensate.
If there is no condensate backup, take the following
steps:
2. Check ionization electrode and connecting cable.
If fault persists, replace BCU burner control unit:
See page 89.
Reset the boiler.
Replace BCU burner control unit:
See page 89.
Reset the boiler.