Mitsubishi Electric QAHV-N560YA-HPB, Service Handbook

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[
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Read Before Servicing ]
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HWE1517A GB
(4) Vacuuming the refrigerant circuit
No.
1
2
3
4
5
6
High-pressure service valve
Low-pressure service valve
CO
2
valve
CO
2
manifold
Vacuum valve
Refrigerant service port
CO
2
cylinder
–
Vacuum pump
(with a check valve)
Packless valve
Vacuuming hose
Vacuuming hose
–
Scale
Connect the CO
2
cylinder to the gas charging/release
hose that connects to the manifold.
Fully close the low-pressure service valve on the unit.
Connect a packless valve to the vacuum port on the
manifold via a hose, and connect a vacuum pump to
the packless valve (see the figure below).
Make sure the high-pressure service valve, the CO
2
valve on the manifold, and the packless valve are
OPEN.
Make sure the vacuum valve on the manifold, the
low-pressure service valve, and CO
2
cylinder valve are
securely CLOSED.
This is done to evacuate the hose between the unit
and the CO
2
cylinder.
Packless valve is necessary for checking the degree
of vacuum inside the unit. Ordinary hose can be
connected to this valve.
Because residual refrigerant may be present in dry
ice condition, perform vacuuming three times as
shown below.
Vacuum for 30 minutes. →Leave the refrigerant
circuit open to air for 5 minutes. →Vacuum for 30
minutes. →Leave the refrigerant circuit open to air
for 5 minutes. →Vacuum for 60 minutes. →Check
the degree of vacuum five minutes later. →Proceed
to the next step if the degree of vacuum is
satisfactory.
Operate the vacuum pump, and slowly open the
vacuum valve on the manifold to start vacuuming.
The target degree of vacuum is 266 Pa or below.
Cautionary notes Procedure
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