Viessmann Vitocrossal 200 Service Instructions For Contractors page 38

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.
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.
F F4 Poor start-up characteristics,
rotary damper does not
close, solenoid valve does
not switch.
38
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 not gas-tight
(gas is escaping and burn-
ing); incorrect 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
Compensation lines not
connected, servomotor
faulty, servomotor power
cable faulty, solenoid
valve faulty, output relay
of burner control unit faul-
ty
Measures
Insert coding card; check coding
card, replace if required.
Replace coding card or burner
control unit.
I
Danger
Plug-in terminals on the burn-
er 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 burner control unit; replace
burner control unit.
Reset burner control unit; replace
burner control unit.
Check ionisation path; replace cod-
ing card; replace gas train.
Insert plug of ionisation electrode;
check cable; adjust ionisation elec-
trode (see page 23).
Adjust ignition electrodes (see
page 23); replace ignition unit; re-
place burner control unit.
Replace ignition or ionisation elec-
trode.
Check compensation lines and
connections (see page 51), re-
place power cables, replace servo-
motor, replace solenoid valve, re-
place burner control unit.