Viessmann VITOCROSSAL 200 Service Instructions Manual page 61

Fault codes
(cont.)
Displayed System characteris-
fault code tics
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
F F4 Flame does not build
during the safety
time, no signal cap-
tured by the ionisa-
tion flame monitor
F F4 Flame does not build
during the safety
time, no signal cap-
tured by the ionisa-
tion flame monitor
F F5 Air pressure switch
shows no air pres-
sure, fan not running
Cause
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
Gas train does not
open
Combustion char-
acteristics not ide-
al
Air pressure switch
is faulty, incorrectly
connected or incor-
rectly set
Troubleshooting
Measures
Adjust ignition electrodes
(see page 40); replace ig-
nition unit; replace burner
control unit
Replace ignition or ionisa-
tion electrode
Replace connecting ca-
ble; replace servomotor;
replace burner control
unit
Select the gas type (see
from page 11)
Check connecting cable;
check gas train and re-
place if required
Adjust the burner (see
from page 27); if necessa-
ry also adjust the setting
screws when the burner is
off to be able to start the
burner
Replace air pressure
switch, connect correctly
or adjust
61