Viessmann VITOCROSSAL 200 Service Instructions Manual page 42

Troubleshooting
Diagnosis
(cont.)
Fault code System characteris-
tics
26 Ionisation flame mon-
itor reports external
light ingress during
the start or after the
post-purge
26 Ionisation flame mon-
itor reports external
light ingress during
the start or after the
post-purge
26 Ionisation flame mon-
itor reports external
light ingress during
the start or after the
post-purge
26 Ionisation flame mon-
itor reports external
light ingress during
the start or after the
post-purge
27 Flame tears off dur-
ing operation
27 Flame tears off dur-
ing operation
27 Flame tears off dur-
ing operation
27 Flame tears off dur-
ing operation
27 Flame tears off dur-
ing operation
29 Burner control unit
fault
2A Burner control unit
fault
2b Burner control unit
fault
42
Cause
Ignition cables
shorted out
Ionisation cable or
electrode short cir-
cuit
Gas train leaks
Incorrect parame-
ter set selected
Incorrect gas type
selected
Burner gauze
assembly faulty
Incorrect parame-
ter set selected
Combustion char-
acteristics not
ideal
285 kW burner for
open flue opera-
tion
Internal fault of the
gas pressure
switch input
Internal fault of the
air pressure switch
input
Internal flame
monitor fault
Measures
Remove the short circuit.
Remove the short circuit.
Replace gas train.
Adjust the parameter set
(see page 36 to 37).
Adjust gas type (see
page 9).
Replace the burner gauze
assembly.
Adjust the parameter set
(see page 36).
Adjust burner (see from
page 14).
Adjust burner settings
(see page 46).
Replace burner control
unit.
Replace burner control
unit.
Replace burner control
unit.