6-12
Evacuation and Cleanup of System
Refrigeration Maintenance and Service Operations
CRR-20 & CRR-40, September 1999
mm (1/4 inch) diameter hose as it does through a 13 mm (1/2
inch) diameter hose. It takes twice as long to pull a vacuum
through a 2 meter (6 foot) long hose as it does through a 1
meter (3 foot) long hose.
Heat Saves Time
A useful and practical time saver is the application of heat to
the system. Increasing the temperature of the compressor oil
and refrigerant will speed up the vaporization of any water
present in the system.
WARNING: Never use a torch or other concentrated
heat source to heat the compressor or other refriger-
ation system component.
Heat lamps, electric heaters, or fans can be applied to the
compressor crankcase and other parts of the system to increase
the temperature of the refrigerant and compressor oil.
Unit Charging (from an Evacuated Condition)
1.
Close valve V4.
2.
Open the Gas Ballast valve (located on top of the pump
housing behind the handle).
3.
Stop the vacuum pump.
4.
The discharge valve and receiver outlet valves remain
mid-seated.
5.
Connect the refrigerant tank with gauge manifold to the
evacuation station (see “Evacuation Station and Unit
Hookup” in this chapter).
6.
Weigh the tank of refrigerant.
7.
Check the unit data plate for the required weight of refrig-
erant charge then subtract the amount of the charge to be
input to your unit from the total weight of the tank of
refrigerant. This provides final tank weight after the unit
receives a full system refrigerant charge.
8.
Set the refrigerant tank for liquid removal. Open the hand
valve on the tank.
9.
With the unit OFF, open the gauge manifold hand valve
and charge liquid refrigerant into the system.
Constant Pressure Rise After Evacuation Indicates
System Leak
1. Close the vacuum valve and watch the movement of
vacuum gauge needle. If needle continues to rise,
this is an indication that a leak exists in the unit or
connecting line. The leak must then be located and
eliminated.
2. Time
3. Pressure (Vacuum)
4. Atmospheric Pressure
Pressure Rise Levels Off After Evacuation Indicates
Moisture in System
1. Close the vacuum valve and watch the movement of
vacuum gauge needle. If needle shows a pressure
rise but finally levels off to a constant pressure, the
system still contains too much moisture.
Dehydration and additional evacuation time are
required.
2. Time
3. Pressure (Vacuum)
4. Atmospheric Pressure
Содержание CRR-20
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