Viessmann Vitocrossal 200 Service Instructions Manual page 41

Diagnosis
(cont.)
Fault code System character-
istics
22 The gas pressure
switch signals no
gas pressure during
the safety period
25 No flame signal
after the safety peri-
od; the ionisation
flame monitor re-
ports no flame sig-
nal
25 No flame signal
after the safety peri-
od; the ionisation
flame monitor re-
ports no flame sig-
nal
25 No flame signal
after the safety peri-
od; the ionisation
flame monitor re-
ports no flame sig-
nal
25 No flame signal
after the safety peri-
od; the ionisation
flame monitor re-
ports no flame sig-
nal
25 No flame signal
after the safety peri-
od; the ionisation
flame monitor re-
ports no flame sig-
nal
25 No flame signal
after the safety peri-
od; the ionisation
flame monitor re-
ports no flame sig-
nal
Cause Remedy
Gas shut off valve Open the gas shut off
closed, gas pres- valve and check the gas
sure switch faulty supply pressure; clean
the gas filter, if required.
Ionisation elec- Adjust the ionisation
trode incorrectly electrode (see page 24).
adjusted
Ignition electro- Adjust the ignition elec-
des incorrectly trodes (see page 24).
adjusted
Insulation body of Replace the ignition
the ignition elec- electrodes.
trodes cracked
Incorrect gas type Adjust the gas type (see
selected page 9).
The gas combina- Check the gas combina-
tion valve does tion valve and replace it,
not open if required.
Combustion char- Adjust the burner (see
acteristics not from page 14).
ideal
Troubleshooting
41