When the air conditioning system on your vehicle is serviced, federal law requires the old refrigerant in the system to be recovered BEFORE any repairs are made that require opening up the A/C system. Refrigerant recovery prevents refrigerant from escaping into the atmosphere. R-12 can damage the ozone, and R-134a is a greenhouse gas that contributes to global warming.
Refrigerant recovery requires a refrigerant recovery machine that meets Society of Automotive Engineers (SAE) standards: SAE J2209 for R-12, or SAE J1732 for R-134a, or J1770 for a combination R-12/R-134a recovery machine. If a repair shop does not have a refrigerant recovery machine (and a certified technician who knows how to use it), they cannot legally service your A/C system.
Recovery and recycling equipment also must be approved by Underwriters Laboratories (UL approved). It also must have a desiccant package to trap moisture, and an in-line particulate filter (15 micron size) to trap contaminants. The machine also must purge noncondensable gases (NCGs) automatically or warn the operator when the NCG level is exceeded to minimize the risk of air contamination. The equipment must also shut off automatically when the recovery tank is filled to 80% of capacity. In addition, any technician who uses the equipment must be trained and "certified" in recovery and recycling service procedures.
The Environmental Protection Agency does not want technicians venting refrigerant when servicing vehicles. For many years, this was a common practice because refrigerant was relatively cheap and no one realized it was causing any harm. Today, R-12 is scarce and expensive, and we know it is harmful to the ozone layer.
It is illegal to vent any type of refrigerant from a vehicle, including R-12, R-134a or any other alternative refrigerant. The prohibition against venting includes even a small charge of refrigerant that may have been added to a vehicle for purposes of detecting a leak. If there is any refrigerant in the system at all, it must be recovered and not allowed to escape. Period.
Venting has been outlawed because man-made chlorofluorocarbons (CFCs) such as R-12 damage the Earth's protective ozone layer that shields us from most of the sun's harmful ultraviolet radiation. Scientists have discovered that CFCs react with ozone in such a way that ozone is destroyed faster than it can be replenished by natural processes. The result has been a measurable thinning of the ozone layer and a big increase in UV exposure, which increases the risk of skin cancer.
To make matters worse, CFCs break down very slowly. R-12 is estimated to have an atmospheric lifespan of nearly 100 years! So any R-12 that leaks out of a vehicle's A/C system today will still be eating holes in the ozone layer a century from now! That is why recovery is so important.
Reducing global warming is another reason not to vent refrigerants. R-134a contains no chlorine and poses no danger to the ozone layer, but like R-12, it is a "greenhouse" gas that retains heat and contributes to the global warming problem. The "Global Warming Potential" (GWP) rating of R-134a is 1,200, which compares to 7,300 for R-12, but only 1.0 for carbon dioxide. So every pound of refrigerant that leaks or escapes into the atmosphere has the same effect as thousands of pounds of CO2.
Some recovery and recycling machines have a built-in refrigerant identifier. This feature prevents accidental cross-contamination of refrigerants, as well as cross-contamination in the equipment itself. As many as one out of every 10 vehicles on the road today may contain cross-contaminated refrigerant!
There is no way to know for sure what kind of refrigerant is actually in a vehicle without testing it. An identifier will tell you what is in the system and its degree of purity. Most will also detect dangerous flammable hydrocarbons such as propane or butane. If the indentifier detects the wrong type of refrigerant or a flammable refrigerant, it stops the recovery process and warns the operator.
The law requires a separate recover and recycling machine for each type of refrigerant: one for R-12, one for R-134a and a third machine if a shop works with any alternative refrigerants. To keep costs down, some suppliers offer "combination" recovery and recycling machines that can do both R-12 and R-134a using separate internal circuits, pumps, filters and storage tanks. Some of these machines have two separate compressors while others share a common compressor and use a self-cleaning purge cycle to prevent cross-contamination of refrigerant lubricants.
Purity standards are also important. Recycling equipment must meet SAE J1991 for R-12 (no more than 15 ppm moisture, 4,000 ppm of refrigerant oil and 150 ppm of noncondensable gases/air by weight), and/or SAE J2099 for R-134a (no more than 50 ppm of moisture by weight, 500 ppm of refrigerant oil, and 150 ppm of noncondensable gases/air by weight).
If a shop does a lot of A/C service work, a combination recovery/recycling/charging station may provide the best all-round service solution. The latest generation of A/C service equipment combines identification, recovery/recycling, vacuum purging, recharging, pressure readings and refrigerant identification into one machine. On the more sophisticated models, most of these functions are automated so the technician does not have to babysit the machine while it pulls out the refrigerant and recharges the system. Additional features may include automatic oil purging after recovery, automatic air purging from the recovery tank to minimize the risk of air contamination, and the ability to capture and record important system data (minimum and maximum system pressure, outlet duct temperatures, amount of refrigerant charge in system, etc.).
A highly accurate scale is also essential. Most vehicles today have reduced refrigerant capacity (under 2 lbs.), which means charging accuracy is extremely important to avoid overcharging the system. This requires a highly accurate scale (plus or minus 1 oz.) for measuring the amount of refrigerant used. If a shop has an older machine that cannot achieve this level of accuracy, you should find another repair facility that has up-to-date A/C service equipment.
Using a recovery/recycling machine is not difficult. The basic procedure goes as follows:
1. Connect the hoses on the recovery machine to the service fitting on the vehicle.
2. Turn the recovery unit on following the equipment manufacturer's operating instructions. Allow the machine to continue pulling refrigerant from the system until it indicates all of the refrigerant has been recovered (system pressure reads vacuum and holds vacuum for at least 5 minutes). If the machine does not have an automatic timer or shut-off, discontinue recovery at this time, and close and disconnect the service hoses.
TIP: If A/C components show evidence of icing during the recovery process, the components can be gently heated to speed up the flow of refrigerant. Use a hot air blow dryer, never any type of open flame, to heat parts.
3. Once the recovery process is complete, determine how much oil was pulled out along with the refrigerant so you can replace it when the system is recharged. Most machines have an oil cup that will show how much oil was taken out. The cup should usually have about one ounce of oil in it if the system contains the proper amount of oil. If the system is low on oil, there may be little or no oil in the cup. On the other hand, if the system is overcharged with oil, there may be several ounces of oil in the cup.
4. After the refrigerant has been recovered, the recycling process can begin. The time it takes to clean the refrigerant can vary from 20 minutes up to an hour depending on the amount of contamination. During the recycling phase, the refrigerant is filtered and dried. Particulates, moisture, oil and air are all removed until the refrigerant meets purity standards. A moisture indicator light usually signals when the job is done. The refrigerant can then be put back into the vehicle, or saved and reused in another vehicle.
Most machines use "single-pass" recycling where the refrigerant makes only one pass through the cleaning circuit, but some machines also offer "multi-pass" recycling or a choice of single-pass or multi-pass cleaning. Multi-pass cleaning takes longer but may be necessary with refrigerant that contains a lot of moisture.
The filter-drier that removes particulates and moisture from the refrigerant needs to be replaced periodically. Filter capacities vary somewhat from one machine to another, and lifespan depends on how much crud and moisture the filter picks up from the refrigerant. But as a rule, a typical filter will usually clean about 1,000 lbs. of refrigerant before it has to be replaced.
Other equipment you should also have to service A/C systems today includes:
Effective October 31, 2008, the EPA requires all new refrigerant recovery equipment to meet SEA standard J2810, which replaces the earlier J1732 standard. The new rules require refrigerant recovery equipment to do a much better job of extracting all of the refrigerant from an A/C system. Under the old standard, as much as 30% of the refrigerant could still remain inside the A/C system after a recovery operation. The new standard requires the recovery equipment to pull out 95% of the refrigerant within 30 minutes.
NOTE: This standard does NOT require auto repair shops to replace existing A/C recovery equipment with new equipment that meets the higher standard. But if new equipment is purchased after October 31st, 2008, the new equipment must be certified to the new J2810 standard.
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