Midea MCHSU-09PHH2, Service Manual, Page: 71 / 81

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6). Disconnect the charge set and the charging
cylinder, and open the 2-way and 3-way valves
Be sure to use a hexagonal wrench to operate
the valve stems.
7). Mount the valve stems nuts and the service
port cap.
Be sure to use a torque wrench to tighten the
service port cap to a torque 18N.m.
Be sure to check for gas leakage.
12.4.6 Re-Installation When the Outdoor
Unit Requires Repairs
1. Evacuation for the whole system
Procedure:
1).Confirm that both the 2-way and 3-way
valves are open.
2). Connect the vacuum pump to 3-way valve’s
service port.
3). Conduct an evacuation for approximately
one hour. Confirm that the compound meter
displays a value of -0.1Mpa(14.5Psi).
4). Close the valve (Low side) on the charge set,
turn off the vacuum pump. After 5 minutes,
confirm that the gauge needle is not moving.
5). Disconnect the charge hose from the
vacuum pump.
2. Refrigerant charging
Procedure:
1). Connect the charge hose to the charging
cylinder. Open the 2-way 3-way valve.
With the charge hose you disconnected from
the vacuum pump, connect it to the valve at the
bottom of the cylinder. If the refrigerant is
R410A, place the cylinder bottom-up to ensure
liquid charge.
2). To purge the air from the charge hose, open
the valve at the bottom of the cylinder and press
the check valve on the charge set (be careful of
the liquid refrigerant).
3) Place the charging cylinder onto the
electronic scale and record the weight.
4). Open the valves (Low side) on the charge
set and charge the system with liquid refrigerant
If the system cannot be charged with the
specified amount of refrigerant, or can be
charged with a only a small amount at a time
(approximately 150g each time),turn the unit on
in cooling mode; however, one time is not
sufficient, wait approximately 1 minute and then
repeat the procedure.
5).If the electronic scale displays the proper
weight, disconnect the charge hose from the
3-way valve’s service port immediately.
If the system has been charged with liquid
refrigerant while the air conditioner is on, turn
off the air conditioner before disconnecting the
hose.
6). Mount the valve stem caps and the service
port.
Use a torque wrench to tighten the service port
cap to a torque of 18N.m.
Be sure to check for gas leakage.
12.5 Drainage pipe installation
Install the drainage pipe as shown below and
take measures against condensation.
Improperly installation could lead to leakage
and eventually wet furniture and belongings.
12.5.1 Installation principle