Viessmann VITODENS 343-F WS4A Installation And Service Instructions Manual page 24

Commissioning, inspection, maintenance
Further details regarding the individual steps
24
(cont.)
1. Check the inlet pressure of the dia-
phragm expansion vessel.
2. Close the gas shut-off valve.
3. Pivot control unit A down (see
page 23.)
4. Fill the heating system at fill valve
B in heating return B. minimum
system pressure > 0.8 bar (see
pressure gauge C behind the
hinged cover).
Note
If the control unit had not already
been switched ON before filling
began: The diverter valve is in cen-
tre position and the system will be
completely filled.
5. If the control unit had already been
switched ON before filling began:
In code 1, set coding address
"2F:2" (see page 66).
At this point, the diverter valve is in
its central position.
Whilst the fill program runs, the dis-
play shows "bF" (constant tem-
perature control unit) or "Filling"
(weather-compensated control
unit).
6. Close boiler fill & drain valve .
7. Set coding address "2F:0".