Refrigerant Service Stations
Refrigerant service stations recover, evacuate, and recharge automotive air conditioning systems. These machines are dedicated; refrigerants are not to be mixed. A refrigerant identifier is used to ensure the correct refrigerant is in the system. Mixed refrigerants are stored in a gray container with a yellow top.
The recovery process involves retrieving the refrigerant from the system, drying and filtering it, and then storing it in a storage tank located in the cabinet for use in this vehicle or another. After the gauge reads zero, wait 10 minutes or so to see if the gauge increases, indicating the system is not empty. Repeat the recovery process if necessary.
Evacuating an automotive air conditioning system removes damaging moisture from the system. Moisture enters the system as a vapor and must be heated to its boiling point before it's removed with a vacuum pump. Drawing a closed A/C system into a vacuum lowers the boiling point so that the moisture can be vaporized and drawn out of the system. The system can be leak tested by allowing the system to rest for a specified period and monitoring the gauge. If the gauge increases .01 inches of mercury or more, the system should be leak tested.
Charge the system by weight. Most of today's machines have a database of refrigerant charges by vehicle year, make, and model. A passenger car may hold 1.5 pounds of refrigerant. In comparison, a passenger van with dual units may contain 7 or 8 pounds of refrigerant. Always replace the exact amount of oil lost during recovery. Machines have a collection bottle, and manufacturers publish lists with the specific amounts to be added when replacing different components.