An air conditioner is made of a host of components that work together to bring you the cool conditioned air throughout your home that you desire. One of the many components is the capacitor. The capacitor is a component that works with your air conditioner’s compressor. Essentially the capacitor stores energy and sends a jolt of power which switches the motor on and off. When there is a problem with the capacitor, your air conditioning unit may have a hard time switching on or not coming on all together. Steve’s Heating & Air will walk you through the steps of testing the capacitor to see if it’s broken or failing.
Tools to Test an Air Conditioner Capacitor
Before you get started, you will need three essential tools: one a screwdriver that has an insulated handle, second, insulated gloves, and third, a meter that is designed to read micro-farads or a meter with resistance such as OHMS. As a word of caution, you will be near high voltage wiring and for those unfamiliar with electrical testing; it is strongly recommended you avoid doing your own testing. Instead, have a professional HVAC technician do the testing for you as they are trained in electrical safety.
How to Test an AC Capacitor
Step 1. Start by turning off the circuit breaker that provides power to the outside unit. Also turn your thermostat down to a much lower temperature and select the cooling option. This will still send about 24 volts of power to the capacitor. However, it’s not enough to turn on the fan or run the compressor.
Step 2. Make sure the outdoor air conditioning unit is turned off and not running. You may still hear a humming sound. If you hear humming, go back inside and switch the thermostat into the off position.
Step 3. Go back outside and remove the panel covering. This should expose the electrical components.
Step 4. With your insulated gloves and screwdriver, touch the “C” or connection tab and the “HERM” which is the compressor tab at the top of the capacitor. This will discharge the “HERM” side of the capacitor.
Step 5. Next touch the “C” connection and the “FAN” tabs which will discharge the “FAN” side of the capacitor. The tabs for both the “FAN” and “HERM” should be labeled.
Step 6. You will want to make a note to which color wires are connected to each terminal. Each brand varies. However in most cases the brown wire connects to the “FAN” the red connects to “C” and Purple to the other “C” and the yellow to the “HERM.” Then remove each wire after you’ve recorded where each color connected to each terminal.
Step 7. There are two ways you can test the capacitor. One is by using the micro-farads meter and place one lead on the “C” and the other on the “FAN” or “HERM.” The correct operating range should be located in the capacitor. If it is within proper range then the capacitor is still good. The second method uses an OHMS meter. Once again place one of the leads on the “C” and the other one on either the “FAN” or “HERM.” Once again the charge range should be on the capacitor. Check to see if the charge is within proper range. Each capacitor operating range varies. If the capacitor range is correct the capacitor is still good. If the capacitor failed to produce proper micro-farads or OHMS range then you mostly like need to replace the capacitor.
Step 8. Replace the wiring using your notes. Make sure they are in the correct place. Once complete, replace the electrical cover panel back on and switch the power back on.