Viessmann VITOCAL 242-S Installation And Service Instructions Manual page 72

Commissioning, inspection, maintenance
Further details regarding the individual steps
72
3. Fill (flush) and vent the secondary cir-
cuit:
■ Slightly open the quick-action air
vent valve (see safety assembly,
chapter "Connecting the secon-
dary circuit"); it remains open.
■ For venting, use lever to move the
3-way diverter valve for "Heating/
DHW heating" to its centre position
and click into place: See diagram.
!
4. Please note
To prevent equipment dam-
age, check the flow and return
connections of the secondary
circuit at the heat pump for
tightness.
In the case of leaks, switch off
the appliance immediately,
drain the water and check the
seating of the seal rings.
Always replace displaced seal
washers.
5. Check system pressure. Top up with
water if required.
Minimum system pressure:
0.8 bar (80 kPa)
Permiss. operating pressure:
3 bar (0.3 MPa)
(cont.)