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
start chemical changes that can result in corrosion and eventual breakdown of the chemicals in the system. The smallest amount of moist air in the refrigerant system might start reactions that can cause malfunctions.

Whenever it is necessary to disconnect a refrigerant line, wipe away any dirt or oil at and near the connection to eliminate the possibility of dirt entering the system. Both sides of the connection should be immediately capped or plugged to prevent the entrance of dirt, foreign material, and moisture. It must be remembered that all air contains moisture. Air that enters any part of the system
carries moisture with it.

Keep all tools clean and dry. This includes the gauge set and replacement parts. Be careful not to overtighten any connection. Overtightening can result in distortion and a system leak.

When adding oil, the container and the transfer tube through which the oil will flow should be exceptionally clean and dry. Refrigerant oil quickly absorbs any moisture it contacts. For this reason, the oil container should not be opened until it is time to use it and should be capped immediately after use.

When it is necessary to open a system, have everything needed immediately available so as little time as possible is required to perform the operation. Do not leave the system open any longer than necessary.

Any time the system has been opened for repairs, it must be properly evacuated after the repair. Also, before disconnecting or removing any part, the refrigerant needs to be recovered and not allowed to escape the atmosphere.