Viessmann Vitodens 100 Installation And Service Instructions Manual page 61

Fault finding
(cont.)
Display fault System char-
code acteristics
F2 Burner in fault
state
F3 Burner in fault
state
F4 Burner in fault
state
F5 Burner
blocked
F8 Burner in fault
state
F9 Burner in fault
state
FA Burner in fault
state
Cause
Temperature limit-
er has responded.
The flame signal is
already present at
burner start.
No flame signal is
present.
Air pressure
switch faulty
Fuel valve closes
too late
Fan speed too low
at burner start
Fan not at stand-
still
Troubleshooting
Remedy
Check the heating sys-
tem water level. Check
the circulation pump.
Vent the heating system.
Check the temperature
limiter and leads.
Press "Reset".
Check the ionisation
electrode and leads.
Press "Reset".
Check the ionisation
electrode and leads,
measure the ionisation
current, check the gas
pressure, check the gas
combination valve, igni-
tion, ignition module and
condensate drain.
Press "Reset".
Check the air pressure
switch and the intercon-
necting cable.
Check gas combination
valve. Check both control
paths.
Press "Reset".
Check the fan, check the
fan cables and supply,
check the fan control.
Press "Reset".
Check the fan, check the
fan cables, check the fan
control.
Press "Reset".
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