Viessmann VITOCAL 222-S Installation And Service Instructions Manual page 53

Filling and venting the secondary side
!
Please note
Escaping liquids can lead to electrical defects.
Protect electrical components of the heat pump
from escaping liquids.
Fig. 49
Commissioning, inspection, maintenance
(cont.)
1. Open any non-return valves installed on site.
2. Check the pre-charge pressure of the expansion
vessel.
Technical guide
3. Fill (flush) and vent the secondary circuit:
Slightly open quick-action air vent valve, remains
■
open: See safety assembly, chapter "Connecting
the secondary circuit".
■ Open air vent valve DHW heating, remains open:
See the following chapter.
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
Leaking hydraulic connections lead to appli-
ance damage.
Check tightness of the internal and on-site
■
hydraulic connections.
■ In the event of leaks, switch off the appli-
ance immediately. Drain off liquid via the
drain valve. Check the seating of seal
rings. Always replace displaced seal rings.
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)
53