Viessmann Vitocrossal 200 Service Instructions For Contractors page 52

Troubleshooting
Fault codes
(cont.)
Displayed System characteris-
fault code tics
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
F F5 Air pressure switch
switches off during
operation
F F6 Gas pressure switch
notifies no gas pres-
sure
F F7 Fan pressure is pro-
duced during the air
pressure switch idle
state check
F F7 Air pressure switch
contact is not in the
idle state
F F8 Flame tears off dur-
ing operation
F F8 Flame tears off dur-
ing operation
52
Cause
Gas train does not
open
Combustion char-
acteristics not ide-
al
Air pressure switch
is faulty, incorrectly
connected or incor-
rectly set
Flue gas back
pressure; conden-
sate banked up; air
pressure switch
hose faulty; con-
necting hose leak-
ing
Gas shut-off valve
closed; gas pres-
sure switch faulty;
multiple problems
with gas supply
Wind influence on
fan
Air pressure switch
faulty
Incorrect gas type
selected
Burner gauze as-
sembly faulty
Measures
Check connecting cable;
check gas train and re-
place if required
Adjust the burner (see
from page 19); 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 or set cor-
rectly
Remove flue gas back
pressure; check if con-
densate banked up; reset
burner control unit; re-
place hose
Open gas shut-off valve;
check gas flow pressure;
replace gas filter if re-
quired; reset burner con-
trol unit; replace gas train
Check flue outlet (chim-
ney)
Replace air pressure
switch
Selecting the gas type
(see from page 10)
Check burner gauze as-
sembly; replace if dam-
aged