Electronic Combustion Control Unit - Viessmann VITODENS 343-F WS4A Installation And Service Instructions Manual

Remote control DIP switches
Remote control
The remote control affects the heating
circuit without mixer A1
The remote control affects the heating
circuit with mixer M2
When connecting a separate room
temperature sensor, set DIP switch "3"
to "ON".

Electronic combustion control unit

The electronic combustion control unit
utilises the physical correlation
between the size of the ionisation cur-
rent and the air factor . In case of air
factor 1, the maximum ionisation cur-
rent results for all gas qualities.
The ionisation signal is evaluated by
the combustion control unit, and the
air factor is adjusted to between
=1.24 and 1.44. This range provides
for an optimum combustion quality.
Thereafter, the electronic gas valve
regulates the required gas volume
subject to the prevailing gas quality.
(cont.)
DIP switch setting
To check the combustion quality, the
CO content or the O
2
flue gas is measured. The actual
values enable the prevailing air factor
to be determined. The relationship
between the CO
2
air factor is illustrated in the follow-
ing table.
Function description
content of the
2
or O content and
2
127