Viessmann Vitocrossal 200 Service Instructions Manual page 40

Troubleshooting
Diagnosis
Faults with indication on the display and programming unit
Message codes
Message System character-
code istics
A Burner OFF
A Burner OFF
A Burner is in a fault
state
L Air pressure switch
responds during op-
eration
P System OFF
General process error
Fault code System character-
istics
20 Fan pressure is pro-
duced during the air
pressure switch idle
state check
20 The air pressure
switch contact is not
in the idle state
21 Air pressure switch
shows no air pres-
sure, fan does not
operate
21 Fan does not run
40
Cause Remedy
Gas pressure Check the gas pressure
switch fault switch
Lack of gas Notify your gas supply
company
See fault code See fault code steps
Flue gas back Check condensate
pressure, con- drain, remove flue gas
densate banked back pressure, reset the
up burner control unit in ac-
cordance with the de-
tails on page 31.
Incorrect para- See acknowledging a
meter set se- parameter set, page 36.
lected
Cause Remedy
Wind influence on Check the flue gas
fan draught (chimney).
Air pressure Replace the air pressure
switch faulty switch.
Air pressure Replace the air pressure
switch faulty switch.
Fans are faulty, Check cables and re-
cables are faulty place the fan, if re-
or broken quired.