SALES RESTRICTION
As of November 14, 1994, the sale of CFC and HCFC refrigerants is restricted to certified technicians. Only techni‐
cians certified under Clean Air Act Section 609 (Motor Vehicle Air Conditioning) are allowed to purchase refrigerants in
containers smaller than 20 lbs.
SUBSTITUTE REFRIGERANTS AND OILS
Our industry is in a state of change. New refrigerants, blends of older refrigerants, and different oils have ap‐
peared in the field.
R‐134a is a HFC and is considered Ozone friendly. R‐134a is the leading candidate for CFC R‐12 retrofit, but it is not a
drop‐in substitute. Actually, there isn't a drop‐in alternative, but R‐134a can be used in most R‐12 systems by following
appropriate retrofit procedures. R‐134a will not mix with most refrigerant oils. The oils used in most R‐134a refrigera‐
tion systems are ESTERS. Esters cannot be mixed with other oils. It is also important to remember that when leak testing
an R‐134a system to use pressurized nitrogen.
There are several refrigerant blends commonly in use. Some of the blends are called Ternary, which means they are a
three‐part blend. Ternary blends are used with a synthetic alkylbenzene lubricant. Make certain you are using the cor‐
rect oil for the refrigerant. Most refrigerant oils are hygroscopic. Hygroscopic oil has a high affinity for water. An oil
sample should be taken and analyzed if a system has had a major component failure.
There is some specific information you will need to know about blends. First, the components of a blended refrigerant
will leak from a system at uneven rates due to different vapor pressures. Second, the proper charging method for
blended refrigerants is to weigh into the high side of the system as a liquid. A term you will need to know is
“temperature glide”. Temperature glide refers to a refrigerant blend that has a range of boiling points or condensing
points throughout the evaporator and condenser respectively
Other blends may be azeotropic. An azeotropic mixture acts like a single component refrigerant over its entire tem‐
perature / pressure range. An azeotrope does not have a temperature glide.
RECOVERY TECHNIQUES
Now that recovery is the law, many contractors have increased their service rates to help offset the cost of recovery
equipment and recovery time. Some customers have complained about the increased cost of service. To justify the in‐
crease, simply explain that you are duty bound and required by law to recover refrigerants in order to protect the envi‐
ronment and human health.
EPA regulations require a service aperture or process stub on all appliances that use a Class I or Class II refrigerant in order
to make it easier to recover refrigerant.
When servicing a system, if you discover that two or more refrigerants have been mixed in a system, you must re‐
cover the mixture into a separate tank. It is important NOT to mix different refrigerants in the same recovery tank be‐
cause the mixture may be impossible to reclaim. Recover only one type of refrigerant into a recovery cylinder.
If a strong odor is detected during the recovery process, a compressor burn‐out has likely occurred. When recovering re‐
frigerant from a system that experienced a compressor burn‐out, watch for signs of contamination in the oil. After
recovering refrigerant, if nitrogen is used to flush debris out of the system, the nitrogen may be legally vented. A suc‐
tion line filter drier should be installed to trap any debris that may damage the new compressor.
The length of the hose between the unit being recovered from and the recovery machine will greatly effect the effi‐
ciency of the recovery process. Long hoses will cause excessive pressure drop, increased recovery time, and have a po‐
tential for increased emissions. Since all refrigerants have a pressure temperature relationship, the lower the ambient
temperature, the slower the recovery rate.
After completing the transfer of liquid refrigerant between a recovery unit and a refrigeration system, you should
guard against trapping liquid refrigerant between the service valves.
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