Viessmann Vitocrossal 200 Service Instructions For Contractors page 51

Fault codes
(cont.)
Displayed System characteris-
fault code tics
F F2 Burner control unit in
a fault state; system
cools down
F F3 Ionisation flame mon-
itor reports faulty
flame signal during
start-up or after the
post-purge
F F4 No flame formation
during safety time;
ionisation flame mon-
itor reports no flame
signal
F F4 No flame formation
during safety time;
ionisation flame mon-
itor reports no flame
signal
F F4 No flame formation
during safety time;
ionisation flame mon-
itor reports no flame
signal
F F4 Poor start-up charac-
teristics; rotary damp-
er does not close
F F4 Flame does not build
during the safety
time, no signal cap-
tured by the ionisa-
tion flame monitor
Cause
Excessive boiler
water temperature
Gas train not gas-
tight (gas is escap-
ing and burning);
incorrect coding
card
Ionisation elec-
trode incorrectly
adjusted; ionisa-
tion electrode not
plugged in. Earth
leakage of elec-
trode or cable
Ignition electrodes
incorrectly adjus-
ted, electrodes
earthed, faulty igni-
tion unit, faulty
burner control unit
Insulation body of
ignition or ionisa-
tion electrode
cracked
Servomotor faulty,
servomotor con-
necting cable faul-
ty, output relay
faulty (burner con-
trol unit)
Incorrect gas type
selected
Troubleshooting
Measures
Wait until temperature
falls below the permiss.
boiler water temperature;
reset burner control unit
Check ionisation path; re-
place coding card; re-
place gas train
Insert plug of ionisation
electrode; check cables;
adjust ionisation elec-
trode (see page 32)
Adjust ignition electrodes
(see page 32); replace ig-
nition unit; replace burner
control unit
Replace ignition or ionisa-
tion electrode
Replace connecting ca-
ble; replace servomotor;
replace burner control
unit
Selecting the gas type
(see from page 10)
51