Re-Charging AC Systems with R134a, Uncategorized

Charging Your Retrofit Air Conditioning System: 3 Important Safety Tips

Note: Charging procedures for the Perfect Fit retrofit air-conditioning systems by Classic Auto Air is different than most modern air-conditioning systems. Please read and follow all procedures and safety precautions carefully.

So you’ve bought and installed your new Classic Auto Air Perfect Fit air-conditioning system and now need to get the system charged. Our first tip is to find a qualified technician that will charge your new retrofit A/C system. We have created a checklist that can be used at a charging station, or for hand charging. But it’s important to note that the charging procedures for this system are different than most modern AC systems.  A qualified technician will avoid damaging your new AC system.

Do not charge your perfect fit system with your car running!

Commercial charging stations which add 134a, charge refrigerant in a liquid form which will damage the Sanden-style compressor if the refrigerant is added while the vehicle is running. Unlike the common procedures used for many late-model vehicles which have variable speed compressors, this retrofit system cannot be charged with the car running. This is important! Failure to follow this warning will direct liquid refrigerant into the compressor piston chamber. Flooding the compressor piston chamber will likely cause damage to the compressor reed valves and/or pistons as well as potentially seizing the compressor (and sadly voiding your warranty!) After charging the system, you must hand-turn the compressor 15 to 20 revolutions before starting the car.

Evacuate the system before charging!

Your qualified technician will connect his service equipment gauges to the high and low charging ports. Before charging your retrofit air-conditioning system, it’s important to evacuate the system for a minimum of 30 to 45 minutes. A longer if possible is preferable. This evacuation removes any moisture and will reveal any small leaks in the system. Your technician should make sure the low side reaches a minimum of 28 to 30 inches of vacuum. Failure to evacuate the system will cause inadequate cabin cooling temperatures, internal freeze-up, and premature component failure.

Do not overcharge the system!

Unfortunately, many backyard tree shade mechanics may only have experience working on older compressors, operating with inaccurate information regarding how to identify a fully charged system. Back in the “good old days,” when charging A/C systems using R12 refrigerant, mechanics were told to look through a sight glass on the top of the receiver/drier. They were instructed to stop filling the system when they could no longer see bubbles. This new air-conditioning system requires R134a refrigerant. We no longer use a clear glass porthole to visually determine how much refrigerant to use. Your new air conditioner requires 1.5 pounds or 24 ounces of R134a refrigerant. Adding more than the recommended amount of refrigerant will not lead to cooler temperatures.

Read our blog piece on undercharged and overcharged air-conditioning systems for more tips and safety information. One additional note is hand charging using canned refrigerant from an auto parts store. Do not shake tilt or turn the cans of refrigerant upside down while charging refrigerant must come out of the top of the can shaking tilting or inverting the can upside down may cause the reed valves in the compressor to be damaged and will void your warranty. Again, note the maximum charge amount is 24 ounces (two 12-ounce cans.)

By closely following our guidelines, your qualified technician will have your system charged and cooling your car in no time. And remember, we’re always here to help. If you have any questions before, during, or after charging, please call us toll-free at 1-866-435-7801. Stay cool and happy motoring!

 

 

Related Posts

6 thoughts on “Charging Your Retrofit Air Conditioning System: 3 Important Safety Tips

  1. GILL says:

    Is this A/C charging procedure apply to all Sanden Compressors? Or only to your retro kits?

  2. kevin says:

    Had a backyard mechanic do mine. Gets real cold but the car overheats. Could charging it wrong cause it to run hotter thus overheating the radiator?

  3. Richard Middleton, ASE Master Auto & Truck Tech says:

    Thank you for your attention to detail on the 134 systems. Back in the Good Ole Days…a mechanic could also make the mistake of trying to charge on the hi side as the fittings were same thread. Disaster! The Good Ole Days were not always so good. It’s best to have a 134 system charged at a certified and legal shop where 134 amounts can be weighed. The Shop can also provide better evacuation pump systems. Money well spent!
    Thanks again…you have great street rod system coverage!

  4. Terry Anderson says:

    Two questions,
    I have a system using the Sandon type compressor with R-12. Should it be serviced with the engine not running?
    If R134A is serviced with vapor only, should the engine be running or stopped?

  5. Terry says:

    IE: Perfit fit for 70 Mustang. I installed system, evacuated system, I cant get system to take 134a. Only takes a little. Maybe 1/3 can. What am I doing wrong?
    479-530-5313

  6. jack dunn says:

    Is there any safe way to hand charge this compressor? I do not have an air conditioning expert close by. I have gauges etc. but no charging station.

Leave a Reply

Your email address will not be published. Required fields are marked *