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Proper Methods For
Refrigerant Removal.
Removal of refrigerant from a system can be accomplished by one of two basic methods: passive or active. To comply with government regulations and best serve customer needs, time must be taken to evaluate the system and determine which method to employ.
Questions to be considered by the technician:
* Is the system compressor operable?
* Is the system sufficiently accessible?
* Where is the liquid refrigerant within the system?
* What is the outside (ambient) temperature?
* Will outside conditions have any effect?
If the system is not analyzed, recovery could take longer than necessary.
Passive Recovery
System-dependent (passive) recovery is the recovery of refrigerant from a system employing the refrigeration systems internal pressure and/or compressor to aid the recovery process. System-dependent equipment cannot be used with appliances containing more than 15 pounds of refrigerant.
To make it easier for technicians to recover refrigerant, the EPA is requiring manufacturers to install a service aperture or process stub for appliances containing Class I and II refrigerants. If a service technician uses passive or system-dependent recovery on a system with an inoperative compressor, the refrigerant must be recovered from both the low and high side of the appliance, to speed the recovery process and achieve the required recovery efficiency requirements.
A vacuum pump can be used in this procedure. However, never discharge a vacuum pump into a pressurized container. Vacuum pumps cannot handle pumping against anything but atmospheric pressure. If the compressor is operative, refrigerant can be recovered from the high side only.
In all passive recovery, the refrigerant must be recovered in a nonpressurized container. Whether or not the compressor is operative, gently striking the compressor with a wood or rubber mallet during recovery will agitate and release the refrigerant dissolved in the compressor's crankcase oil.
Refrigerant can be removed without damage to the compressor, contingent on the following:
* An adequately sized receiver or condenser;
* Weight recording method;
* Proper on-off controls; and
* Adequate recovery containers (not exceeding the container's maximum net weight).
Active Recovery
The most common method of system refrigerant removal is through use of a certified, self-contained recovery unit. Self-contained (active) recovery equipment has it own means of removing refrigerant from appliances...