Viessmann VITODENS 111-W Installation And Service Instructions Manual page 57

Fault display
(cont.)
Displayed System characteris-
fault code tics
F2 Burner in a fault
state
F3 Burner in a fault
state
F4 Burner in a fault
state
F8 Burner in a fault
state
F9 Burner in a fault
state
FA Burner in a fault
state
FC Burner blocked
Cause
Temperature limit-
er has responded
Flame signal is al-
ready present at
burner start
No flame signal de-
tected
Fuel valve closes
too late
Fan speed too low
during burner start
Fan idle state not
reached
Electrical fan con-
trol (control unit)
faulty
Troubleshooting
Measures
Check heating system fill
level. Check circulation
pump. Vent the system.
Check the temperature
limiter and connecting ca-
bles (see page 64).
Press "Reset" (see
page 58).
Check ionisation elec-
trode and connecting ca-
ble.
Press "Reset" (see
page 58).
Check the ionisation elec-
trode and connecting ca-
bles, the gas pressure,
the gas train, ignition and
condensate drain.
Press "Reset" (see
page 58).
Check gas train. Check
both control paths.
Press "Reset" (see
page 58).
Check fan, fan connecting
cables and power supply;
check fan control.
Press "Reset" (see
page 58).
Check fan, fan connecting
cables and fan control.
Press "Reset" (see
page 58).
Check fan connecting ca-
ble; replace if required, or
replace control unit.
57