Viessmann Vitodens 333 Service Instructions Manual page 78

Troubleshooting
Fault codes
(cont.)
Fault Const. Weath.-
code in comp.
the dis-
play
F8 X X
F9 X X
FA X X
Fd X X
FE X X
FF X X
78
System char- Cause
acteristics
Burner fault The fuel
valve closes
too late
Burner fault Fan speed
too low dur-
ing burner
start
Burner fault Fan not at
standstill
Burner Fault burner
blocked control unit
Burner Strong inter-
blocked or in a ference
fault state (EMC) field
nearby or
faulty main
PCB
Burner Strong inter-
blocked or in a ference
fault state (EMC) field
nearby or in-
ternal fault
Remedy
Check the gas
combination valve
and both control
paths; press "E"
Check the fan, fan
connecting
cables, fan power
supply and con-
trol; press "E"
Check fan, fan
connecting cables
and fan control;
press "E"
Check the ignition
electrodes and
connecting
cables/leads;
check whether
there are strong
fields of interfer-
ence (EMC) near
the equipment;
press "E". Re-
place the control
unit if the fault
persists.
Start the boiler
again. Replace
the control unit if
the equipment will
not restart.
Start the boiler
again. Replace
the control unit if
the equipment will
not restart.