Diagnosis - Viessmann VITOCROSSAL 200 Service Instructions Manual

Troubleshooting

Diagnosis

Faults with fault indicator on the display and programming unit
Message codes
Message System characteris-
code tics
A Burner off
A Burner off
F Burner is in a fault
state
L Air pressure switch
switches off during
operation
P System off
General process errors
Fault code System characteris-
tics
20 Fan pressure is pro-
duced during the air
pressure switch idle
state check
20 Air pressure switch
contact is not in the
idle state
21 Air pressure switch
shows no air pres-
sure, fan not running
21 Fan does not run
22 The gas pressure
switch signals no gas
pressure during the
safety time
40
Cause
Gas pressure
switch fault
Lack of gas
See fault code
Flue gas back
pressure, conden-
sate banked up
Incorrect parame-
ter set selected
Cause
Wind influence on
fan
Air pressure switch
faulty
Air pressure switch
faulty
Fan faulty; cables
are faulty or bro-
ken
Gas shut-off valve
closed, gas pres-
sure switch faulty
Measures
Check the gas pressure
switch
Notify your gas supply util-
ity
See fault code steps
Check condensate drain,
remove flue gas back
pressure, reset the burner
control unit in accordance
with the details on
page 32 .
See acknowledging a
parameter set, page 37.
Measures
Check the flue draught
(chimney)
Replace the air pressure
switch
Replace the air pressure
switch
Check cables and replace
the fan if required
Open the gas shut-off
valve and check the gas
flow pressure; clean the
gas filter if required