Mitsubishi Electric QAHV-N560YA-HPB, Service Handbook

Page: 15 / 176

[
I
Read Before Servicing ]
- 8 -
HWE1517A GB
(3) Gas leak test
No.
1
2
3
4
5
–
High-pressure service valve
Low-pressure service valve
Gas charging/
release side
CO
2
valve
CO
2
manifold
Vacuuming valve
To unit Refrigerant service port
Nitrogen cylinder
Pressure
reduction
valve
Connect a pressure reduction valve to the nitrogen
cylinder, and then connect the cylinder to the gas
charging/release hose that connects to the manifold.
Connect the manifold to the high-pressure service
valve. Fully close the low-pressure service valve. CO
2
manifold has a structure different than that of
HFC manifold. Refer to the “[5] CO
2
refrigerant
manifold structure” in the Attachment.
Charge the unit with nitrogen, adjusting the pressure
with the reduction valve to 8.5 MPa. Once the charging
pressure reaches 8.5MPa, shut off the nitrogen cylinder
valve. Use caution because the charging pressure is high.
Charge nitrogen from the high-pressure side.
Test the brazed areas for gas leak, using foaming
solution. Make sure there is no leak.
When the leak test is done, slowly open the
low-pressure service valve to release the nitrogen. Be careful that nitrogen may suddenly gush out.
Purge the nitrogen only from the low-pressure side
or from both the low- and high-pressure sides
simultaneously, but not only from the high-pressure
side.
Cautionary notes Procedure
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