Owners of other similar HVAC condenser units from manufacturers such as Gibson, Rheem, Trane, GE (General Electric), Mars, Carrier, York, Lennox, Frigidaire, Kenmore, Mitsubishi, Maytag, and Whirlpool may also find this guide to be helpful.

The most obvious sign of a dual run capacitor that needs to be replaced is that the A/C air handler inside your home will only blow room temperature air out of the vents or "registers".

Another symptom of a faulty dual run capacitor is that both the condenser's fan and compressor components will not start working. You may instead just hear a faint electrical humming sound.

Usually, the condenser fan motor can be manually started up by spinning it with a small stick.

If you have a GE Mars or Rheem A/C system, you may be better served by my capacitor replacement guides for those two specific manufacturers. Click on the blue links in the previous sentence to visit the pages.

The panel is located on the only corner of the condenser unit that does not contain vent holes and there is a large wire loom coming out of the bottom of the panel.

Remove them with a flathead screw driver and set them aside in a safe place.

Pull the panel down and away from the corner of the condenser unit.

Be careful! The capacitor and other components may still contain dangerous voltage and could cause an electrical shock if touched with bare hands or metal tools.

There are several common methods for discharging the dangerous voltage stored in a dual run capacitor.

They include using a rubber handled screwdriver to short all of the terminals (possibly dangerous), using a resistor attached to insulated wire leads (safest), and using a motor/bulb or other electrical device attached to wires.

If your dual run capacitor is bulging, has swollen sides or is leaking a greasy and/or oily substance, it may already be discharged and definitely needs to be replaced. Avoid touching the greasy gel or oily liquid leaking from the capacitor since some older capacitors were manufactured with carcinogenic (cancer causing) chemicals known as PCBs.

Once the capacitor is discharged, you can safely pull off the wires from the terminals using rubber handled needle nose pliers or rubber glove covered hands. Take note of which colored wires attach to which terminal.

There are three terminals on a dual run capacitor. The terminals are usually marked with the following symbols - "C" (common), "F" (fan), and "HERM" (hermetic compressor). You can also sometimes differentiate the terminals by the number of connection points they have. The "C" (common) terminal usually has four, the "HERM" (compressor) usually has three, and the "F" (fan) terminal has only one or two.

On this Goodman GSC130361FA condenser, the "C" Common terminal of the dual run capacitor was attached to the red (RD) and purple (PU) wire. The "F" FAN terminal was connected to the brown (BR) wire and the HERM compressor terminal was attached to the yellow (YL) wire.

The old capacitor is held in place by a single metal strap secured with a single flathead screw. Hold the base of the capacitor with one hand while loosening the screw until it can easily slipped out of the band.

A replacement capacitor can be purchased at a variety of places such as an appliance parts supply warehouse, an HVAC parts wholesale store, online retail websites such as Amazon, or you might be able to buy one at a premium price from your local A/C repair company.

It's best to take the old part with you when you guy to buy the new one to ensure that you purchase a replacement capacitor with the correct microfarads and voltage rating.

A new capacitor, depending on the type, could range in price from about $10 to around $40 with the most common price being between between $25 and $30.

If the only suitable replacement capacitor available is oval instead of round, or round instead of oval, it will still work fine. You may just need to adjust the metal retaining strap or find a different way to securely mount the capacitor.

Double check that all of the wires are securely plugged into the proper places on top of the new dual run capacitor before re-attaching the electrical access panel and tightening the two flathead screws.

Turn on the condenser's power breaker switch outside, flip on the HVAC power breaker switches inside the house, turn on the air handler's breaker switch (if you turned it off), and turn on the A/C system at the thermostat.

You should hear the condenser's compressor motor click on and the fan motor start spinning. Then shortly afterward, the air handler should begin blowing cool air through the home's A/C vents.
 

Please check out my full list of DIY Home Repair & Maintenance Guides.