Viessmann VITOCROSSAL Service Instructions Manual page 73

Fault codes
(cont.)
Fault code dis- System characteristics
played
EF Burner in a fault state
F0 Burner blocked
F1 Burner in a fault state
F2 Burner in a fault state
F3 Burner in a fault state
F6 Burner in a fault state
F9 Burner in a fault state
FA Burner in a fault state
FC Burner in a fault state
FD Burner in a fault state and ad-
ditional fault b7 is displayed.
FD Burner in a fault state
Cause
Flame is lost immediately
after it has built (during
safety time).
Internal fault
Flue gas temperature lim-
iter has responded.
Temperature limiter has
responded.
Flame signal is already
present at burner start.
Temperature values of the
boiler water temperature
sensors vary too widely
from one another.
Fan speed too low during
burner start
Fan idle state not reached Check the fan. Check the fan con-
Gas train faulty, modula-
tion valve control faulty or
flue gas path blocked
Coding card missing.
Burner control unit fault
Troubleshooting
Measures
Check gas supply (gas pressure
and gas flow switch).
Check balanced flue system for
flue gas recirculation.
Check ionisation electrode (replace
if required):
Distance to burner gauze assem-
■
bly (see page 24)
Contamination on electrode
■
Press reset button R.
Replace control unit.
Check heating system fill level.
Vent the system.
Press reset button R after flue sys-
tem has cooled down.
Check heating system fill level.
Check circulation pump. Vent the
system. Check temperature limiter
and connecting cables.
Press reset button R.
Check ionisation electrode and
connecting cable.
Press reset button R.
Replace the boiler water tempera-
ture sensors.
Check the fan. Check the fan con-
necting cables. Check the fan pow-
er supply. Check the fan control.
Press reset button R.
necting cables. Check the fan con-
trol.
Press reset button R.
Check gas train. Check flue sys-
tem.
Press reset button R.
Insert coding card.
Press reset button R.
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 button R.
Replace control unit if fault per-
sists.
73