An AC capacitor is a small metal cylinder, usually silver or black, shaped like a soda can or an oval tube, mounted inside the outdoor condenser cabinet behind the access panel. The top has two or three metal terminals labeled with markings like HERM, FAN, and C (common). Most homes have a single dual-run capacitor that powers both the compressor and the condenser fan. A healthy capacitor is flat on top and clean. A failed one is easy to spot: the top bulges or domes upward, it may be leaking oily fluid, or the casing is split. A blown capacitor is the single most common AC repair, it causes the unit to hum without starting, or the fan to sit still. The obvious physical defects isn't the only way to tell if a capacitor is going bad, you can also connect the HERM and C connectors and test the MFDs, this is usually the main way you are able to tell if a capacitor is bad. It is also a high-voltage part that holds a charge even when power is off, so it is not a safe DIY swap. Call LA Heating & Air at (818) 660-1062.
