Commissioning, inspection, maintenance
Further details regarding the individual steps
Filling and venting the heating system
!
Please note
Unsuitable fill water increases
the level of deposits and corro-
sion and may lead to boiler dam-
age.
■ Flush the heating system thor-
oughly before filling.
■ Only use fill water of potable
quality.
■ Soften fill water with a hard-
ness above 16.8 °dH
(3.0 mol/m
water softening system for
heating water (see the Vitoset
pricelist).
■ Antifreeze suitable for heating
systems can be added to the fill
water. The antifreeze manufac-
turer must verify its suitability,
as damage to gaskets or dia-
phragms and noise during
heating operation may other-
wise occur. Viessmann
accepts no liability for any
resulting damage or conse-
quential losses.
1. Check the pre-charge pressure of the
diaphragm expansion vessel.
2. Close the gas shut-off valve.
18
3
), e.g. with a small
3. Fill the heating system at the fill valve
in the heating return (on site).
Minimum system pressure > 0.8 bar
(80 kPa).
Note
If the control unit was not switched on
prior to filling the system, then the
servomotor of the diverter valve will
still be in its central position and the
system will be completely filled.