Midea 9V SERIES, Service Manual

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Caution:
Capacity test is based on standard length and maximum allowance length is based on reliability.
Oil trap should be installed per 5-7 meters.
6.4 Air purging with vacuum pump
Air and moisture in the refrigerant system have undesirable effects as below:
●
Pressure in the system rises.
●
Operating current rises.
●
Cooling or heating efficiency drops.
●
Moisture in the refrigerant circuit may freeze and block capillary tubing.
●
Water may lead to corrosion of parts in the refrigerant system.
Therefore, the indoor units and the pipes between indoor and outdoor units must be leak tested and
evacuated to remove gas and moisture from the system.
Air purging with vacuum pump
(Indoor unit)
(Liquid side)
(Gas side)
Vacuum
pump
Vacuum
pump
adaptor
Lo Hi
Handle Hi
Two-way valve
Close
Manifold valve
Compound meter
Pressure
gauge
-76cmHg
Handle Lo
Charge hose
Charge hose
(Outdoor unit)
Close
Three-way valve