Air Purging Of The Piping And Indoor Unit - Midea MSC-09HRDN1-QD0(E) Service Manual

7.4 Air purging of the piping and indoor unit

Required tools:
Hexagonal wrench; adjustable wrench; torque wrenches, wrench to hold the joints and gas leak detector.
Note:
The air in the indoor unit and in the piping must be purged. If air remains in the refrigeration piping, it will affect the
compressor, reduce the cooling capacity, and could lead to a malfunction of unit.
Be sure, using a torque wrench to tighten the service port cap (after using the service port), so that it prevents the gas
leakage from the refrigeration cycle.
Procedure
1. Recheck the piping connections.
2. Open the valve stem of the 2-way valve
counterclockwise approximately 90', wait 10
seconds, and then set it to closed position.
Be sure to use a hexagonal wrench to operate the
valve stem.
3. Check for gas leakage.
Check the flare connection for gas leakage
4. Purge the air from the system.
Set the 2-way valve to the open position and
remove the cap from the 3-way valve's service
port.
Using the hexagonal wrench to press the valve
core pin, discharge for three seconds and then wait
for one minute.
5. Use torque wrench to tighten the service port cap
to a torque of 1.8 kg.m. (18n.m)
6. Set the 3-way valve to the opened position.
7. Mounted the valve stem nuts to the 2-way and
3-way valves.
8. Check for gas leakage.
At this time, especially check for gas leakage from
the 2-way and 3-way stem nuts, and from the
service port.
Caution:
If gas leakage is discovered in step (3) above, take the
following measures.
If the leaks stop when the piping connections are
tightened further, continue working from step (4).
If the gas leaks do not stop when the connections are
retightened, repair the location of the leak, discharge all
of the gas through the service port, and then recharge
with the specified amount of gas from a gas cylinder.
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