Viessmann VITODENS 200-W Service Instructions Manual page 106

Function description
Electronic combustion control unit
Air factor CO /O
2 2
Air factor O content
2
(%)
1.24 4.4
1.27 4.9
1.30 5.3
1.34 5.7
1.37 6.1
1.40 6.5
1.44 6.9
To achieve an optimum combustion
control, the system regularly carries
out an automatic self-calibration; also
after a power failure (shutdown). For
this, the combustion is briefly regu-
lated to max. ionisation current
(equals air factor =1). The automatic
calibration is carried out shortly after
the burner start and lasts approx. 5 s.
This may lead to CO emissions in
excess of 1000 ppm for a short time.
106
content
CO content
2
(%) for natur-
al gas E
9.2
9.0
8.7
8.5
8.3
8.1
7.8
The combustion control unit can also
be calibrated manually. e.g. after
maintenance or service work (see
page 88).
(cont.)
CO content CO
2
(%) for natur- (%) for LPG P
al gas LL
9.1 10.9
8.9 10.6
8.6 10.3
8.4 10.0
8.2 9.8
8.0 9.6
7.7 9.3
content
2