How to Convert (Retrofitting) R-12 Air Conditioning System to R-134a

The following guidelines should be followed when converting an older A/C system to R-134a. These guidelines should allow you to provide the customer with a cool vehicle and to meet current legislative mandates.

A label showing that an R-12 A/C system was converted to R-134a. This must be attached to the vehicle whenever the conversion has taken place.

The guidelines are listed in order and reflect the necessary steps for making this conversion.

1. Visually inspect all A/C and heater system components.
2. Use a refrigerant identifier to make sure the system only contains R-12.
3. Check the system for

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Automobile Air-conditioning: REFRIGERANT SAFETY PRECAUTIONS

Air-conditioning (A/C) service, in many ways, is different from service to other parts of the vehicle. Although there are few parts in the system, each component has a specific purpose and service procedure.

R-12 should be stored and sold in white containers, whereas R-134a should be stored in light blue containers.

That by itself is not a big deal. The challenge with the A/C is how it operates. The system operates on changes of refrigerant pressure. There are many things that can cause the pressure to change; some are part of the system, some are part of the environment, and some of them are faults or bad components in the system.

There are some precautions when you work with refrigerants.

1. Always work in a well-ventilated and clean area. Refrigerants are colorless and invisible. Refrigerant is heavier than oxygen and will displace it in a confined area. Avoid breathing the refrigerant vapors. Exposure to refrigerant may irritate your eyes, nose, and throat.
2. Refrigerant evaporates quickly when it is exposed to the atmosphere. It will

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Automobile Air-conditioning: Service Precautions

A/C systems are extremely sensitive to moisture and dirt. Therefore, clean working conditions are very important. The smallest particle of foreign matter in an A/C system contaminates the refrigerant, causing rust, ice, or damage to the compressor. For this reason, all replacement parts are sold in vacuum-sealed containers and should not be opened until they are ready to be installed in the system. If, for any reason, a part has been removed from its container for any length of time, the part must be completely flushed using only the recommended solvent to remove any dirt or moisture that might have accumulated during storage. If the system has been open for more than 2 minutes, the entire system must be completely evacuated and a new accumulator or desiccant bag must be installed.

A late-model air-conditioning system.

It is important to remember that just one drop of water added to the refrigerant will

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