Checking The Expansion Vessel And System Pressure; Filling And Venting The Dhw Cylinder On The Dhw Side; Testing The Anode Connection - Viessmann VITOCAL 151-A Installation And Service Instructions Manual

Commissioning, inspection, maintenance

Checking the expansion vessel and system pressure

Use the calculation to DIN 4807-2 to check whether
■
the installed expansion vessel is adequate for the
system water volume.
If the expansion vessel fitted is insufficient, equip the
secondary circuit on site with an additional expan-
sion vessel.
Check the pre-charge pressure of the expansion
■
vessel once a year.
Carry out this test on a cold system.
1. Drain the system until "0" is shown on the pressure
indicator.
Calling up system pressure
Operating instructions.

Filling and venting the DHW cylinder on the DHW side

1. Open all DHW draw-off points in the building.
2. Open the on-site drinking water supply.

Testing the anode connection

Fig. 61
80
C B A
2. If the pre-charge pressure of the expansion vessel
is lower than the static system pressure: Top up
with nitrogen at the valve of the diaphragm expan-
sion vessel until the pre-charge pressure is 0.1 to
0.2 bar (10 to 20 kPa) higher than the static system
pressure.
Note
■ Do not allow the pre-charge pressure to fall
below 0.7 bar (70 kPa) (boiling noises).
■ Factory-set pre-charge pressure: 0.75 to 0.95 bar
(75 to 95 kPa)
3. Top up with water until the charge pressure of the
cooled system is at least 1.0 bar (0.1 MPa), and is
0.3 to 0.5 bar (30 to 50 kPa) higher than the pre-
charge pressure of the expansion vessel: See
chapter "Filling the system".
Permiss. operating pressure: 3 bar (0.3 MPa)
3. Once air stops coming out of the DHW draw-off
point, the DHW cylinder is completely filled.
1. Remove thermal insulation
2. Check that earth cable
tive magnesium anode
3. Insert thermal insulation
.
C
B is connected to protec-
.
A
.
C