Updated April 2018

How to Recharge Your Central Air Conditioner

Often, an A/C unit needs to be topped-off. You can tell when it's low, if the coil inside the house is icing up, or it just doesn't cool down like it did in the past. When the coil ices up, the air is cold but the ice restricts the airflow, and the house just won't get cool. If the A/C system is empty, don't just add freon, because air and moisture have fouled the system. If your gauge needle flutters or bounces around, you've got bigger problems, and you will have to call in a professional.

You can go to www.epatest.com or a similar place and get an EPA certification to purchase R-22.

Let's begin.

Turn off the A/C unit.

Where the tubing meets the outside A/C unit, you will need to remove the two caps.

Make sure the gauge valves are closed, then:

1. Attach the hose for the BLUE gauge to the larger tube. (low pressure side)
2. Attach the hose for the RED gauge to the smaller tube. (high pressure side)
3. Attach the middle hose to the freon tank.

Bleed a little freon through the hoses by loosening the fittings near the gauge set. This is to purge any air from the hoses.

Turn on the A/C unit. Set the thermostat at the coldest setting.

Determine the outside temperature with your thermometer and add 30.
(outside temp 90 degrees + 30 = 120 degrees).

This is your target number on the temperature scale for R 22 on the RED gauge.

Open the BLUE valve to add freon.

When the reading on the RED gauge matches your temperature calculation, close the BLUE valve.

Close freon tank, and disconnect hoses.

Replace A/C unit valve caps.

Go inside.

Place your thermometer in an air vent.

Compare the wall thermostat to your thermometer in the air vent. There should be a difference of 15 - 20 degrees between the inside temp and the cool air coming out of the vent.