Air Purging By Refrigerant - Heat Controller A-VMH18DC-1 Service Manual

Heat Controller, Inc.
the pressure can't achieve -0.1Mpa after pumping 50 minutes, please check if there are some leakage
points. Once the meter indicates -0.1mpa, 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
comes out, then tighten the flare nut again. Make sure the pressure display in the pressure indicator is a
little higher than the atmospheric 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 purge by 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 for gas leakage by checking the flare connections using the soap water method.
5). Discharge the refrigerant by closing the valve on the charging cylinder and discharging the refrigerant
by loosening the flare nut on the 2-way valve approximately 45° until the gauge indicates 0.3 to 0.5 Mpa.
6). Disconnect the charge set and the charging cylinder, and set the 2-way and 3-way valves to the open
position.
Be sure to use a hexagonal wrench to operate the valve stems.
VMH SerieS
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Service Manual