The Correct Capacitor for AC Central Units

Manufacturer's Specifications

• Thousands of different makes and models of central air conditioning units exist in the world. All use different starting capacitors based upon what the engineers specify. If you have a manual, the correct specification may be in there. If not, contact the manufacturer with the model and style of your unit. Parts departments may carry the correct data, and may even stock the correct capacitor.

Capacitor Testing

• Removing and replacing a capacitor is dangerous work that involves risk of electrocution. It requires a specialized knowledge of electrical systems, and it is best left to a qualified technician. Ask the technician to test the capacitor to determine if its good or bad. After testing, more than likely he can match one according to make and model of your unit.

Capacitor Matching

• If you have the knowledge base to correctly remove and replace a capacitor, remove it from the unit. Test the capacitor to find out if it is bad. Capacitors usually have the voltage and capacitance stamped on the exterior. Write down the information and obtain a new capacitor from an electrical supply store. Conversely, take the old capacitor with you. If you do not have a capacitance tester, most electrical shops have the equipment to test it for you.

Capacitor Substitution

• Do not substitute the type or style of capacitor. Technicians at My HVAC Parts state that a capacitor should have two or three electrical prongs on top. Replace your capacitor with one that has the same number of prongs. Also, use the same capacitor with the same voltage and M.F.D. rating. M.F.D. stands for micro-farads, and it is a measure of the capacitor's charge-storing properties.