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Vitodens 100-W, B1HE/B1KE Combi Installation/Service
Fault Messages
(continued)
Troubleshooting
Displayed
fault code
System characteristics Cause
Measures
F.377
Burner in a fault state
Post-processing of
ionization adjustment:
Stabilization conditions
for post calibration
not met
Check gas type setting. If fault recurs, replace BCU
burner control unit: See page 89.
Reset the boiler.
F.378
Burner in a fault state
Flame loss during
stabilization or
operating phase
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.
F.379
Burner in a fault state
Flame signal not
present or insufficient
Check ionization electrode connecting cable for
damage and firm seating.
Check ionization electrode; replace if necessary.
Reset the boiler.
F.380
Burner in a fault state
Flame loss
immediately after
flame formation
(during safety time)
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.
F.381
Burner in a fault state
Flame loss during
operating phase
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.
F.382
Burner in a fault state
Error counter has
exceeded limit.
Reset the boiler.
Work through fault analysis using fault history.
F.383,
F.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 boiler.
F.385
Burner in a fault state
Short circuit, signal
1, ionization current.
BCU burner control
unit faulty.
Check ionization electrode and connecting cable.
If fault persists, replace BCU burner control unit:
See page 89.
Reset the boiler.
F.386
Burner in a fault state
BCU burner control
unit faulty
Replace BCU burner control unit:
See page 89.
Reset the boiler.
F.387
Burner in a fault state
Ground fault,
ionization current.
BCU burner control
unit faulty.
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.
F.388
Burner in a fault state
BCU burner control
unit faulty
Replace BCU burner control unit:
See page 89.
Reset the boiler.
