Installation and operating instruction
Gas condensing unit WTC-GB 15-B Compact and WTC-GB 25-B Compact
10 Troubleshooting
83309302 1/2018-05 La
133-196
The following warnings must only be rectified by qualified personnel:
Warning
Cause
Rectification
W 20
Flame failure in safety time
Check gas connection pressure [ch. 7.1.2]
(flow operated safety device).
Check the ionisation electrode, replace if
necessary [ch. 9.1.4].
Clean burner surface, if necessary replace
[ch. 9.1.3].
Check combustion air for contamination.
With room-air-independent operation, check
soundness of flue gas system [ch. 7.3].
Time until flame formation too long, increase
parameter
2.3.5 Correction gas
surge at start
step by step, whilst ob-
serving CO content [ch. 6.6.2.3].
Time until flame formation too long, increase
parameter
2.3.1 Correction gas
quantity at start
step by step, whilst
observing CO content [ch. 6.6.2.3].
Ensure that the flue gas ducts are unimpeded.
Flue gas resistance too high, check condens-
ate drain.
Check flue gas shut off device, if necessary
replace.
Check gas combi valve, if necessary replace.
W 21
No flame formation at burner start
The system restarts.
Requires no action.
W 22
Flame failure during operation
If occurring occasionally:
(e. g. due to strong wind at the flue gas system):
Requires no action.
If occurring frequently:
Check gas connection pressure [ch. 7.1.2]
(flow operated safety device).
Check the ionisation electrode, replace if
necessary [ch. 9.1.4].
Clean burner surface, if necessary replace
[ch. 9.1.3].
Check combustion air for contamination.
With room-air-independent operation, check
soundness of flue gas system [ch. 7.3].
Ensure that the flue gas ducts are unimpeded.
Flue gas resistance too high, check condens-
ate drain.
Check flue gas shut off device, if necessary
replace.