Viessmann Vitocrossal 200 Series Service Instructions Manual page 42

Troubleshooting
Fault codes
(cont.)
Fault code dis- System characteristics
played
F B7 Burner control unit in a fault
state; system cooling down;
burner control unit locked out.
F B7 Type of coding card
F E4 Burner shuts down.
F E5 Burner control unit in a fault
state
F EE Burner control unit in a fault
state
F EF Burner control unit in a fault
state
F F3 Ionisation flame monitor re-
ports faulty flame signal dur-
ing start-up or after the post-
purge.
Ionisation electrode or burner
gauze assembly damaged.
F F4 No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
F F4 No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
F F4 No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
42
Cause
Coding card not inserted
in the burner control unit;
incorrect or faulty coding
card
Coding card does not
match burner control unit.
Multiple detection of un-
dervoltage with recurrence
and renewed undervolt-
age
Internal fault of the burner
control unit and during test
of ionisation input
Internal error in feedback
from gas safety valves.
The output relay does not
respond.
Internal error in feedback
from gas safety valves.
The output relay does not
respond.
Gas train leaks (gas is es-
caping and burning). In-
correct coding card.
Ionisation electrode incor-
rectly adjusted, ionisation
electrode not plugged in.
Earth fault of electrode or
cable
Ignition electrodes incor-
rectly adjusted, electrode
earth fault, ignition unit
faulty, burner control unit
faulty
Insulation body of ignition
or ionisation electrode
cracked
Measures
Insert coding card. Check coding
card. Replace if necessary.
Replace coding card or burner
control unit.
Danger
Plug-in terminals on the
burner control unit are 'live'.
Only replace the coding card
when the burner control unit
has been isolated from the
power supply.
Check the power supply.
Replace burner control unit.
Reset or replace burner control
unit.
Reset or replace burner control
unit.
Check ionisation path. Check ioni-
sation electrode for earth fault.
Check burner gauze assembly for
deformation.
Replace coding card. Replace gas
train.
Insert plug of ionisation electrode;
check cable; check burner gauze
assembly for deformation. Adjust
ionisation electrode (see page 25).
Adjust ignition electrodes (see
page 25); replace ignition unit. Re-
place burner control unit.
Replace ignition or ionisation elec-
trode.