Viessmann Vitocal 222-S Installation And Service Instructions For Contractors page 65

Filling and venting the secondary side
D E
Fig. 58
01. Open any non-return valves installed on site.
02. Check the pre-charge pressure of the expansion
vessel. Recharge if required.
Commissioning, inspection, maintenance
(cont.)
03. Fill (flush) and vent the secondary circuit via an
on-site connection.
C
!
Please note
To prevent appliance damage, check the
B
secondary circuit flow and return connec-
tions to the appliance for leaks.
In the case of leaks, switch off the appliance
immediately, drain the water and check the
seating of the seal rings. Always replace
A
displaced seal washers.
04. Check the system pressure at the pressure gauge.
Top up with water if required.
■ Minimum system pressure:
0.8 bar (80 kPa)
■ Permissible operating pressure:
3.0 bar (0.3 MPa)
05. Move the control unit panel into the service posi-
tion.
F
06. Open the programming unit.
07. Slightly open quick-action air vent valve
remains open.
Connect the on-site hose to secondary circuit air
vent valve .
C
!
Please note
Escaping liquids can lead to electrical
defects.
Protect electrical components from escap-
ing liquids.
08. Open secondary circuit air vent valve
Danger
Escaping hot water and hot steam can
cause serious injury and damage the heat-
ing system.
Only open drain and fill valves when the
heating system is cold.
09. Move 3-way diverter valve
tion: Press and turn anti-clockwise to lock in
D
the "MAN" position. Move lever
position.
10. If necessary, vent the indirect coil in the DHW cyl-
inder using secondary circuit air vent valve
the DHW cylinder.
11. Close secondary circuit air vent valve
12. Turn the 3-way diverter valve clockwise to the
"AUTO" position.
; it
B
.
C
A to its centre posi-
to a vertical
E
for
F
.
C
65