Mitsubishi Electric QAHV-N560YA-HPB Service Handbook page 16

[ I Read Before Servicing ]
(4) Vacuuming the refrigerant circuit
No.
1 Fully close the low-pressure service valve on the unit.
2
Connect the CO
2
hose that connects to the manifold.
3 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).
4 Make sure the high-pressure service valve, the CO
valve on the manifold, and the packless valve are
OPEN.
5
Make sure the vacuum valve on the manifold, the
low-pressure service valve, and CO
securely CLOSED.
6
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.
Low-pressure service valve
High-pressure service valve
Refrigerant service port
HWE1517A
Procedure
cylinder to the gas charging/release
cylinder valve are
2
Vacuum valve
Vacuuming hose
Vacuuming hose
Cautionary notes
This is done to evacuate the hose between the unit
and the CO cylinder.
2
Packless valve is necessary for checking the degree
of vacuum inside the unit. Ordinary hose can be
connected to this valve.
2
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.
CO manifold
2
CO
Packless valve
Vacuum pump
(with a check valve)
- 9 -
–
–
valve
2
CO cylinder
2
Scale
GB