Midea MA9A-24HR-QB4W, Service Manual

Page: 34 / 61

32
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.
2. Air purging by refrigerant
Procedure:
1). Confirm that both the 2-way and 3-way valves are set to the closed position.
2). Connect the charge set and a charging cylinder to the service port of the 3-way valve.
3). Air purging
Open the valves on the charging cylinder and the charge set. Purge the air by loosening the flare nut on
the 2-way valve approximately 45’ for 3 seconds then closing it for 1 minute; repeat 3 times.
After purging the air, use a torque wrench to tighten the flare nut on the 2-way valve.
4). Check the gas leakage
Check the flare connections for gas leakage.
5). Discharge the refrigerant