Note On Automatic Testing Of The Flue Gas Temperature Sensor; Venting The Boiler - Viessmann VITODENS 242-F Installation And Service Instructions Manual

Commissioning, inspection, maintenance
Further details regarding the individual steps

Note on automatic testing of the flue gas temperature sensor

As soon as the time and date have been
set, the control unit automatically checks
the function of the flue gas temperature
sensor.
The display shows: "Flue gas temp
sensor test" and "Active".

Venting the boiler

A
B
48
Note
If the flue gas temperature sensor is
incorrectly positioned, commissioning
will be cancelled and fault message A3
will be shown (see page 145).
1. Close the shut-off valves on the heat-
C
ing water side.
2. Remove cover panel A.
3. Push the drain hose onto air vent
valve B and connect to a drain.
4. Open air vent valve B and fill valve
C in the heating return and vent
using mains pressure (flush) until no
more air noise can be heard.
5. First close air vent valve B.
6. When the required operating pres-
sure has built up, close fill valve C.
Open the shut-off valves on the heat-
ing water side.
7. Remove drain hose from air vent
valve B and retain.
(cont.)