Compressor Replacement Without a Vacuum Pump

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