Viessmann VITOCROSSAL 200 Instructions Manual page 43

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 extinguishes
during operation
27 Flame extinguishes
during operation
27 Flame extinguishes
during operation
27 Flame extinguishes
during operation
29 Burner control unit
fault
2A Burner control unit
fault
2b Burner control unit
fault
2C Burner control unit
fault
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
Internal fault of the
gas pressure lim-
iter input
Internal fault of the
air pressure switch
input
Internal flame
monitor fault
Fault during test of
safety inputs
Troubleshooting
Measures
Remove the short circuit
Remove the short circuit
Replace gas train.
Adjust the parameter set
(see page 37 to 38).
Adjust the gas type (see
page 9)
Replace the burner gauze
assembly
Adjust the parameter set
(see page 37).
Adjust the burner (see
from page 14)
Replace the burner con-
trol unit.
Replace the burner con-
trol unit.
Replace the burner con-
trol unit.
Replace the burner con-
trol unit.
43