Viessmann VITODENS 100-W Installation And Service Instructions Manual page 51

Fault display
(cont.)
Fault code dis- System characteristics
played
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
Fd Burner blocked
FF Burner blocked
Press reset (reset burner control unit)
Tap and hold R for approx. 2 s.
If the fault has been rectified, fault symbol " " disap-
pears and the default display is shown or a further fault
message is displayed.
If the fault persists, the fault message appears again.
Cause
Temperature limiter has
responded
Flame signal is already
present at burner start
There is no flame signal
Fuel valve closes too late
Fan speed too low during
burner start
Fan idle state not reached Check the fan, fan connecting ca-
Electrical fan control (con-
trol unit) faulty
Burner control unit fault
Burner control unit fault
Troubleshooting
Measures
Check heating system fill level.
Check circulation pump. Vent the
system. Check the temperature
limiter and connecting leads (see
page 56).
Press "Reset" (see page 51).
Check ionisation electrode and
connecting cable.
Press "Reset" (see page 51).
Check the ignition/ionisation elec-
trode and connecting cable, gas
pressure, gas train, ignition, igni-
tion module and condensate drain.
Press "Reset" (see page 51).
Check gas train. Check both con-
trol paths.
Press "Reset" (see page 51).
Check the fan, fan connecting ca-
bles, fan power supply and fan
control.
Press "Reset" (see page 51).
bles and fan control.
Press "Reset" (see page 51).
Check fan connecting cable; re-
place if necessary or replace con-
trol unit
Check ignition electrodes and con-
necting cables. Check whether a
strong interference (EMC) field ex-
ists near the appliance.
Press "Reset" (see page 51).
Replace control unit if fault per-
sists.
Check ignition electrodes and con-
necting cables. Check whether a
strong interference (EMC) field ex-
ists near the appliance.
Press "Reset" (see page 51).
Replace control unit if fault per-
sists.
51