How to Put Freon in an RV Air Conditioner

by Robert Sylvus
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An air conditioner in a RV uses refrigerant to chill air passing over an evaporator coil. RV Air conditioning systems with low refrigerant levels need to have refrigerant added to operate at maximum efficiency. Systems that still have some refrigerant in them can have the refrigerant level topped-off, while systems in need of recharging have leaked out all of their refrigerant. Freon, DuPont's brand name for some types of refrigerant, has become the generic term for most types of refrigerant.

Step 1

Identify the correct refrigerant type as marked on the air conditioning unit's specification tag. Use only the type of refrigerant labeled.

Step 2

Remove the air conditioner's cover. They usually have four to six bolts found along a rib near the RV's roof. Use the correct size socket to remove the bolts. Lift the cover straight up to avoid damaging the condensing coil.

Step 3

Remove the RV air conditioner's refrigerant service port cap on the suction side with an adjustable wrench. The suction side has the large copper tube running from the compressor down into the RV, which eventually goes to the evaporator coil. The smaller copper tube runs from the compressor to the exposed condensing coil.

Step 4

Connect the suction side hose on a set of refrigeration manifold gauges to the service port. The hose will screw onto the service port and release a needle valve in the port. The suction side gauge, found on the left, has pressure and temperature readings for several different types of refrigerants.

Step 5

Connect a bottle of the correct refrigerant to the middle hose on the refrigerant gauges. Open the bottle's valve. Purge the middle hose by quickly opening and closing the right hand valve on the manifold.

Step 6

Turn the RV air conditioner on and set the thermostat to its coldest setting. Check the ambient air temperature in the RV in a spot away from the air conditioning vents.

Step 7

Use the pressure-temperature chart located on the RV air conditioner's lid to find the correct refrigerant pressure for the ambient air. The chart will have a row of temperature readings printed next to a row of corresponding refrigerant pressures.

Step 8

Open the suction side valve on the manifold for 60 seconds. This releases refrigerant into the system.

Step 9

Check the suction side gauge pressure at least 60 seconds after closing the valve. Add refrigerant as needed.

Step 10

Close the refrigerant bottle's valve and remove the charging hose. Disconnect the hose from the service port and reinstall the cap. Carefully slide the air conditioner's lid into place and secure it with the bolts.

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