Viessmann VITODENS 333-F WS3A Service Instructions Manual page 80

Troubleshooting
Fault codes
(cont.)
Fault Const. Weath.-
code comp.
on the
display
F0 X X
F1 X X
F2 X X
F3 X X
F4 X X
F7 X X
F8 X X
80
System char- Cause
acteristics
Burner Internal fault
blocked
Burner in a Flue gas
fault state temperature
limiter has
responded
Burner in a The tem-
fault state perature lim-
iter has
responded
Burner in a Flame signal
fault state is already
present at
burner start
Burner in a No flame sig-
fault state nal.
Burner Differential
blocked pressure
sensor faulty
Burner in a The fuel
fault state valve closes
too late
Measures
Replace the con-
trol unit
Check flue gas
path/route; press
"E"
Check the heating
system fill level,
the circulation
pump, the tem-
perature limiter
and interconnect-
ing cables/leads;
vent the system;
press "E"
Check the ionisa-
tion electrode and
interconnecting
lead; press "E"
Check the ionisa-
tion electrode,
ignition, ignition
module, intercon-
necting cables/
leads, gas pres-
sure, gas train
and the ionisation
current;
press "E"
Check differential
pressure sensor
and lead
Check the gas
train and both
control paths;
press "E"