Viessmann VITODENS 100 Installation And Service Instructions Manual page 69

Fault finding
(cont.)
Display System character-
fault code istics
F3 Burner in fault state
F4 Burner in fault state
F5 Burner blocked
F7 Burner blocked
F8 Burner in fault state
F9 Burner in fault state
FA Burner in fault state
Fd Burner blocked
Cause Measures
The flame signal Check the ionisation
is already present electrode and leads.
at burner start Press"Reset".
No flame signal is Check the ionisation
present 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".
Air pressure Check the air pressure
switch faulty switch and the intercon-
necting cable.
Faulty water pres- Check the water pres-
sure sensor sure sensor and the in-
terconnecting cable.
Fuel valve closes Check gas combination
too late valve. Check both con-
trol paths.
Press"Reset".
Fan speed too Check the fan, check
low at burner start the fan cables and sup-
ply, check the fan con-
trol.
Press"Reset".
Fan not at stand- Check the fan, check
still the fan cables, check
the fan control.
Press"Reset".
Burner control Check the ignition elec-
unit fault trodes and leads. Check
whether a strong inter-
ference (EMC) field ex-
ists near the equipment.
Press"Reset".
If the fault is not re-
moved, replace the con-
trol unit.
Troubleshooting
69