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Removing Air From Refrigerator Cooling System Without Vacuum Pump

by Larry Schlussler PhD on September 23rd, 2010

Compressor Replacement Without a Vacuum Pump

Replacement of a compressor requires the use of a vacuum pump.  Solar

Compressor Replacement Without a Vacuum Pump

powered vaccine refrigerators are generally located away from the utility grid.  Most vacuum pumps are powered by AC grid power making compressor replacement difficult.  We have developed a method of removing the air from a system without the use of a vacuum pump.  The method requires the installation of an access valve on the high and low side of the system.

Evacuation Procedure

1 –        With the new compressor installed, turn on the compressor and depress the access valve on the high side of the system.  Monitor the pressure on the low side of the system.  When the pressure is as low as it will go, close the access valve on the high side of the system and turn off the compressor.  This process will take about 5 minutes.

2 –             Charge the low side of the system to approximately 14 psi.

3 –        Wait about 3 minutes for the pressures on the high and low side to equalize.

4 –        Now turn the compressor on and depress the access valve on the high side.  When the pressure on the low side is as low as it will go, let the high side access valve close and turn off the compressor.

5 –             Repeat steps 2, 3 and 4.  Note, on successive evacuations, the low side pressure will not go as low because of the absorption of refrigerant in the compressor oil and it’s slow release.

6 –             Charge the low side of the system to approximately 14 psi.

7 –        Wait 3 minutes for the pressure to equalize.  Turn on the compressor and depress the access valve on the high side.  This time, when gas is no longer coming out the high side access valve, let the valve close.  The air is now purged from the system.

8 –             Charge the system with the appropriate amount of refrigerant and turn on the compressor.

9 –        Make appropriate adjustments in system charge if necessary.em change if necessary.

One Comment
  1. Thank you Sun Frost. This is very useful.

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