Refrigerant Recovery/Recycle Unit Method

As part o f the no-venting regulations, the EPA requires that all refrigerant be recovered from a system before the system can be opened for servicing. Recovery o f all refrigerant actually means recovery to levels considered acceptable by the EPA. The acceptable levels of recovery are defined by a set of required levels of evacuation (Figure SP-2-3) that must be achieved when recovering refrigerant from a system, or component of a system, for the various categories of equipment.

When opening any system, except for small appliances, you must evacuate the system to the vacuum level set forth by the EPA. The EPA defines small appliances as those in which the refrigerant is sealed within the unit at the factory and the amount of charge is five pounds or less. An example of a small appliance is a room air conditioner. For small appliances, the system is considered completely recovered when either 90% of the refrigerant is removed if the unit has a running compressor, or 80% of the refrigerant is removed if the unit has a non-operating compressor. Since it is difficult to know when the 80% to 90% levels are reached, for practical purposes, small appliances can be considered recovered to an acceptable level when evacuated to 0 psig {0 inches of mercury).

There are some exceptions to these EPA recovery evacuation levels. If evacuation to the specified levels is not achievable because of leaks in the system, or if recovery to these levels would contaminate the refrigerant being recovered, you must:
• When possible, isolate the leaking components from the rest of the system.
• Evacuate non-leaking components to the required levels, if they are to be opened.
• Evacuate leaking components to the lowest level attainable without substantially contaminating the refrigerant. This level cannot exceed 0 psig.

Recovery of refrigerant from a system to the evacuation levels specified by the EPA requires the use o f a certified refrigerant recovery unit or recovery/recycle unit. Generally speaking, the greater the vacuum pulled by the recovery unit, the higher the probability that a high percentage of the refrigerant is recovered. Most recovery units are capable of recovering refrigerant from a system in either the vapor or liquid state. Many automatically adjust to liquid or vapor recovery so refrigerant is pulled from the system as efficiently as possible. Because there is a wide difference in the capabilities of recovery or recovery/recycle units made by the various manufacturers, you must always follow the manufacturer’s safety and operating instructions for the recovery unit being used to achieve the best results.

When the refrigerant to be recovered is highly contaminated, such as after a compressor burnout, or when liquid refrigerant is being recovered, it is a good practice to install an external filter-drier in the common center hose of the gauge manifold set connected to the recovery unit. Be sure to orient the filterdrier for correct flow direction.

Keep in mind that recovery units are not vacuum pumps and do not provide that function. If the dehydration/evacuation of a system is required, a vacuum pump must be used. Refer to Service Procedure SP-3 for instructions on the dehydration/evacuation of a system.

A recycle unit is used to dehydrate and purify the refrigerant so that it can be returned to the system in a purer condition than when recovered. Always make sure that the unit used is capable of processing the refrigerant you plan to handle. The dehydrating and purifying capability of recycle units varies from one model and manufacturer to another. Most recycle units circulate the refrigerant through a distillation, filtration, and drying process to achieve the desired refrigerant quality.

When recycling is completed, the refrigerant is cleaned, but not necessarily to the manufacturer’s original specifications. Acid/moisture testing of recycled refrigerant should be performed to verify the quality of recycled refrigerant before placing it back into the system. For instructions on how to perform an acid/moisture test, refer to Service Procedure SP-5. Recycled refrigerant can only be reused in the same system from which it was recovered, or another system owned by the same customer.

Before using a recovery unit or recycling unit to process a different refrigerant than was last processed, the recovery or recycle unit compressor oil must be drained and replaced with new oil. All filter driers must be replaced and the recovery or recycle unit must be evacuated. Always make sure to use a recovery cylinder designated
for use with the type of refrigerant to be recovered or recycled.

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