Viessmann Vitocrossal CRU 800 Service Instructions For Contractors page 40

Troubleshooting
Fault codes with display on burner control unit
Displayed fault System characteristics
code
F E5 Burner control unit in a fault
state
F EB Burner locked out
F EC Burner control unit in a fault
state
F ED 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 F1 Burner control unit in a fault
state; system cools down.
F F2 Burner control unit in a fault
state; system cools down.
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.
40
(cont.)
Cause
Internal fault of the burner
control unit and during test
of ionisation input
Burner not enabled via ex-
ternal contact.
Internal error in feedback
from safety relay.
Internal error in feedback
from ignition relay.
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.
Flue gas temperature lim-
iter has responded
Flue gas temperature
■
too high
Excessive gas through-
■
put
Boiler water temperature
limiter has responded.
Boiler water temperature
too high.
Gas train leaks (gas is es-
caping and burning). In-
correct coding card.
Ionisation electrode incor-
rectly adjusted; ionisation
electrode not plugged in.
Earth leakage 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
Replace burner control unit.
Check component connected to
TR/TR EIN at plug of the
aBÖ
Vitotronic.
Reset burner control unit. Replace
burner control unit if required.
Reset burner control unit. Replace
burner control unit if required.
Reset or replace burner control
unit.
Reset or replace burner control
unit.
Wait until temperature falls below
■
the permissible flue gas tempera-
ture.
Check the system pressure.
■
Check heat exchanger surfaces
■
for contamination.
Reset burner control unit.
■
Check the CO setting.
■
2
Adjust gas throughput in accord-
■
ance with the rated boiler heating
output. See "Specification" for
connected values.
Wait until temperature falls below
■
the permissible boiler water tem-
perature.
Reset 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; adjust ionisation elec-
trode (see page 24).
Adjust ignition electrodes (see
page 24); replace ignition unit. Re-
place burner control unit.
Replace ignition or ionisation elec-
trode.