Staying cool: MVAC maintenance

If you work on motor vehicle air conditioning in your shop, check out these guidelines on refrigerants and the EPA's Clean Air Act.


air conditioning gauges
A proper set of gauges for air conditioning work can provide the information any technician needs to properly diagnose and service an auto air conditioning system. This set has a central sight glass that shows fluids as they are removed and installed in the system. Photos by Scott Nesbitt

If you’re handy with wrenches, you’ll be asked to fix the air conditioning in a car or truck. Turf machinery technicians can handle the technical side of this work but could be in hot water because of the legalism of staying cool.

The EPA says: “Any person who repairs or services a motor vehicle air conditioning (MVAC) system for consideration (payment or bartering) must be properly trained and certified under Section 609 of the Clean Air Act by an EPA-approved program. All technicians servicing MVAC-like appliances must be certified.

“Only EPA-certified technicians are allowed to purchase ozone-depleting substances (ODS) or non-ozone-depleting substitutes used as refrigerants, with limited exceptions.

“Small cans of non-exempt MVAC refrigerant (i.e., containers designed to hold two pounds or less of refrigerant) that have unique fittings, and self-sealing valves can continue to be sold to persons without certification for DIY use on their vehicles.”

For more details, visit and search for Section 609.

These rules seem to conflict. But the people have voted, and cans of refrigerant line store shelves. Search “car A/C” on YouTube, and you’ll find dozens of lessons in air conditioning system diagnosis and service.

So … it’s legal to work for free on your neighbor’s A/C system and not illegal to overcharge him for changing his car’s oil. Remaining unclear: Is there a penalty for releasing refrigerant into the atmosphere during your DIY service work?

The EPA has rules on air conditioning chemicals. Since about 2010, some new cars are made with R1234yf refrigerant. This is an alternate to R134a that appeared in the early 1990s to reduce ozone hole damage blamed on the R12 that was used since the early 1940s. Now R134a is said to trap heat in the atmosphere, so it must go.

automotive refrigerant R134a
Lots of cans of automotive refrigerant R134a are available on this Walmart shelf, allowing uncertified citizens to possibly buy large quantities of the “chill juice” needed to perform the same work as EPA-certified technicians. The only catch is that the uncertified can’t charge for their work.

The new R1234yf is flammable, so there’s risk of personal harm from fire if a gasoline or diesel vehicle is hit, causing the A/C system to leak. The balance between personal risk and global heat rise is still being sorted out by regulators, lawyers and (perhaps) people elected to make such laws, so the timetable seems fluid at this time.

When shopping for stuff to service your personal vehicle’s air conditioning system, be advised all the refrigerants are synthetic compounds made of carbon, fluorine and other elements. Don’t pay extra for a can that boasts the stuff is “synthetic” or called “California R134a.”

Buying R1234yf may produce sticker shock. Up here north of Atlanta, 8 ounces is $30 at NAPA and $45 at AutoZone and Advance and $70 at O’Reilly for a 12-ounce can. Good old R134a is $10 for 12 ounces at Walmart, about $13 at auto parts stores.

You’ll need tools. For under $100 online, you can get a vacuum pump and a real manifold gauge set with a sight glass and red, blue and yellow hoses, with proper couplers. A couple more bucks gets you the adapters to switch between chemistries. Or you could spend $40 up to $150 for a can with a single blue hose and gauge that lets you add refrigerant, but you can’t tell if you’ve added too much, destroying your system.

Individual situations will vary. State laws may restrict purchases or doing certain work. You may need to have a certified technician remove and capture the old refrigerant in your system, leaving you free to refill it. In any event, try to keep your cool if you find all this confusing.

Scott R. Nesbitt is a freelance writer and former GCSAA staff member. He lives in Cleveland, Ga.

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