Viessmann VITOCROSSAL 200 Service Instructions Manual page 50

Troubleshooting
Diagnosis
(cont.)
Fault
CO content too low
2
CO is formed or burner
is very sooty
Excessive flue gas
temperature
50
Cause
Incorrect setting
Too little or too much
air
Insufficient draught in
flue gas system
Excessive gas
throughput
Measure
Check that burner has been adjusted
for the correct gas type, and change
gas restrictor if required (see from
page 11).
Adjust burner in accordance with the
details on page 14
Adjust correctly. Check ventilation of
installation room
Check flue system
Adjust gas throughput in accordance
with rated boiler output (see supply
values, page 71).
Check condition of secondary heat-
ing surfaces of the boiler, and clean
if required