Checking The Function Of The Thermally Activated Safety Valve; Checking The Mixer For Obstructions And Leaks - Viessmann VITOLIG 300 Service Instructions Manual

Inspection and maintenance
11. Checking the diaphragm expansion vessel and . . .
3. Top up the heating system with
water and vent, until the filling pres-
sure of a cool system is higher (0.1
to 0.2 bar) than the inlet pressure
of the diaphragm expansion ves-
sel.

12. Checking the function of the thermally activated safety valve

Only for the Vitolig 300 with 21.0 and
25.9 kW.
1. Activate the valve of the thermally
activated safety valve: Push red
cap A against the valve.
Water must flow from the valve.

13. Checking the mixer for obstructions and leaks

1. Check the mixer for ease of opera-
tion.
20
2. In case of a low throughput, check
the heat exchanger for scaling and
sludge deposits.
Clean, if required.
2. Check the mixer for leaks.
Replace the O-rings in case of
leaks.
(cont.)