Midea MSMTAU-09HRFN8-QRD6GW, Service Manual

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Be sure to use a hexagonal wrench to operate the
valve stems.
2). Connect the charge hose with the push pin of
handle lo to the 3-way valves gas service port.
3). Air purging of the charge hose.
Open the handle Lo valve of the manifold valve
slightly to purge air from the charge hose for 5
seconds and then close it quickly.
4). Set the 2-way valve to the close position.
5). Operate the air conditioner at the cooling cycle
and stop it when the gauge indicates 0.1MPa.
6). Set the 3-way valve to the closed position
immediately
Do this quickly so that the gauge ends up
indicating 0.3 to 0.5Mpa.
Disconnect the charge set, and tighten the 2-way
and 3-way valve’s stem nuts.
Use a torque wrench to tighten the 3-way valves
service port cap to a torque of 18N.m.
Be sure to check for gas leakage.
2.Air purging with vacuum pump
1) Completely tighten the flare nuts of the
indoor and outdoor units, confirm that both
the 2-way and 3-way valves are set to the
closed position.
2) Connect the charge hose with the push pin
of handle lo to the 3-way valves gas service
port.
3) Connect the charge hose of handle hi
connection to the vacuum pump.
4) Fully open the handle Lo of the manifold
valve.
5) Operate the vacuum pump to evacuate.
6) Make evacuation for 30 minutes and check
whether the compound meter indicates
-0.1Mpa. If the meter does not indicate
-0.1Mpa after pumping 30 minutes, it should be
pumped 20 minutes more. If the pressure can’t
achieve -0.1Mpa after pumping 50 minutes,
please check if there are some leakage points.
Fully close the handle Lo valve of the manifold
valve and stop the operation of the vacuum
pump. Confirm that the gauge needle does not
move (approximately 5 minutes after turning off
the vacuum pump).
7) Turn the flare nut of the 3-way valves about
45° counterclockwise for 6 or 7seconds after
the gas coming out, then tighten the flare nut
again. Make sure the pressure display in the
pressure indicator is a little higher than the
atmosphere pressure. Then remove the charge
hose from the 3 way valve.
8) Fully open the 2 way valve and 3 way valve
and securely tighten the cap of the 3 way valve.
6.7 Re-installation while the outdoor unit
need to be repaired
1. Evacuation for the whole system
Procedure:
1). Confirm that both the 2-way and 3-way
valves are set to the opened position.
2). Connect the vacuum pump to 3-way valve’s
service port.
3). Evacuation for approximately one hour.