Checking The Safety Valve Function; Checking The Electrical Connections For Firm Seating; Checking Gas Equipment On The Fuel Cell Module For Leaks At Operating Pressure - Viessmann Vitovalor PA2 Installation And Service Instructions For Contractors

Check the external diaphragm expansion vessel...
Carry out this test on a cold system.
1. Drain the system until the pressure gauge shows
"0".
Alternatively, close the cap valve on the expansion
vessel and reduce the pressure until the pressure
gauge indicates "0".
2. If the pre-charge pressure of the expansion vessel
is lower than the static system pressure, top up
with nitrogen until the pre-charge pressure is 0.1 to
0.2 bar (10 to 20 kPa) higher than the static system
pressure.

Checking the safety valve function

Checking the electrical connections for firm seating

Checking gas equipment on the fuel cell module for leaks at operating
pressure
Danger
Escaping gas leads to a risk of explosion.
Check gas equipment (including inside the appli-
ance) for leaks.
Commissioning, inspection, maintenance
(cont.)
3. Top up with water until the charge pressure of the
cooled system is at least 1.0 bar (0.1 MPa), and is
0.1 to 0.2 bar (10 to 20 kPa) higher than the pre-
charge pressure of the expansion vessel.
Permiss. operating pressure: 3 bar (0.3 MPa)
Note
Only use suitable and approved leak detection agents
(EN 14291) and devices for the tightness test. Leak
detection agents with unsuitable constituents (e.g.
nitrides, sulphides) can cause material damage.
Remove residues of the leak detection agent after test-
ing.
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