Viessmann Vitodens 050-W Installation And Service Instructions Manual page 49

Fault display
(cont.)
Displayed System characteris-
fault code tics
Fd Burner blocked
FF Burner blocked
––– Burner blocked
Reset (reset burner control unit)
À and ¿: press simultaneously.
The display shows –––.
If the fault has been remedied "¨" dis-
appears and the default display or a fur-
ther fault are shown.
Cause
Fault, burner con-
trol unit
Fault, burner con-
trol unit
Communication er-
ror between burner
control unit and
programming unit
Scanning the programming unit soft-
ware version
À and : press simultaneously.
Troubleshooting
Measures
Check ignition electrodes
and connecting cables.
Check whether a strong
interference (EMC) field
exists near the appliance.
Press "Reset" (see
page 49).
Replace control unit if
fault persists.
Check ignition electrodes
and connecting cables.
Check whether a strong
interference (EMC) field
exists near the appliance.
Press "Reset" (see
page 49).
Replace control unit if
fault persists.
Check connecting cable.
Press "Reset" (see
page 49).
Replace burner control
unit or programming unit if
the fault persists.
49