Viessmann VITOCROSSAL 200 Service Instructions Manual page 42

Troubleshooting
Diagnosis
(cont.)
General process errors
Fault Display
*1
code
F AA F AA
F AA F AA
F Ab F Ab
F Ab F Ab
F Ab F Ab
F Ad A
F AE F AE
F AF F AF
F A0 and F A0 and
F A1 F A1
All fault codes are saved to the fault memory and the last 10 can be called up.
*1
42
System charac-
teristics
Fan pressure is
produced during
the air pressure
switch idle state
check
Air pressure
switch contact is
not in the idle
state
Air pressure
switch shows no
air pressure, fan
does not operate
Air pressure
switch shuts down
during operation
Fan does not run
Gas pressure lim-
iter does not signal
gas pressure
Burner control unit
in fault state
Burner control unit
in fault state
Status duration
too long, fan ramp-
up
Cause
Wind influence on
fan
Air pressure
switch faulty
Air pressure
switch is faulty,
incorrectly con-
nected or incor-
rectly set
Flue gas back
pressure, conden-
sate banked up
Fan faulty; cables
are faulty or bro-
ken
Gas shut-off valve
closed, gas pres-
sure limiter faulty
Valve 1 leaking
Valve 2 leaking
Internal fault; fan
cannot reach its
set value
Measure
Check flue gas
draught (chimney)
Replace air pres-
sure switch
Replace air pres-
sure switch, con-
nect or set cor-
rectly
Remove flue gas
back pressure,
check for conden-
sate banked up,
reset burner con-
trol unit
Check cables and
replace fan if
required
Open gas shut-off
valve, check gas
flow pressure and
clean gas filter if
required
Replacing the gas
train
Replacing the gas
train
Replace burner
control unit or fan