Viessmann VITODENS 200-W WB2B Service Instructions For Contractors page 79

Fault codes
(cont.)
Fault Const. Weath.-
code comp.
on the
display
F4 X X
F7 X X
F8 X X
F9 X X
FA X X
System char- Cause
acteristics
Burner in a No flame sig-
fault state nal.
Burner Short circuit
blocked or water
pressure
sensor lead
broken
Burner in a The fuel
fault state valve closes
too late.
Burner in a Fan speed
fault state too low dur-
ing the burn-
er start
Burner in a Fan not at
fault state standstill
Troubleshooting
Measures
Check the ionisa-
tion electrode and
cable, measure
the ionisation cur-
rent, check the
gas pressure,
check the gas
train, ignition,
ignition module,
ignition electro-
des and the con-
densate drain.
Press "E
RESET".
Check the water
pressure sensor
and the intercon-
necting cable.
Check the gas
train. Check both
control paths.
Press "E
RESET".
Check the fan,
check the fan
cables and sup-
ply; check the fan
control.
Press "E
RESET".
Check the fan, fan
connecting cables
and fan control.
Press "E
RESET".
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