How to Add Refrigerant to a Home AC Unit

Home AC units are a convenience that many people enjoy today. The central-air unit is one of the most common ways of providing cool air to your entire home. A compressor pumps refrigerant through a condenser coil, which cools incoming air that is then forced through the rest of the house in ducts by a blower. Sometimes the compressor will need to be refilled with refrigerant in order to keep the air as cool as possible. This is an easy process that a homeowner can do with the right equipment.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Refrigerant gauges
• Cylinder of proper refrigerant (Probably R-22)
• Refrigerant pump
• Bathroom scale

1. Connect the gauge to the fittings on the outside of the compressor unit. The red hose goes on the small line and the blue line goes on the large line. The yellow hose from the gauge connects to the vacuum pump.

2. Turn on the vacuum pump to evacuate the system.

3. Remove the vacuum pump from the yellow line and replace with the refrigerant cylinder.

4. Place the cylinder on the bathroom scale and record the weight. Open the refrigerant cylinder valve wide open. Open the blue valve wide open for a few minutes and watch the scale weight to determine how many pounds of refrigerant are entering system.

5. Start the unit and set the inside thermostat so the unit will run all the time.

6. Check the scale to determine the refrigerant charge and when the amount of refrigerant that has entered the unit (determined by subtracting the current weight from the starting weight) has reached 50 pounds and then close the valves.

7. Open the blue valve and remove the yellow hose from the refrigerant cylinder.

8. Shut off the small side valve at condenser unit and open the low-pressure side valve on gauge set to equalize pressure.

9. Remove all of the fittings from the unit and use as normal.

Tips & Warnings

• Do not remove any connections or components until the system has been discharged and always wear proper protective equipment when working on a refrigerant system.

References

• Refilling a Home AC Unit

Resources

• Background on Central Air Conditioners