A capacitor is like a battery which stores a large amount of energy, which is drained in one hot when used, after which it recharges. In an HVAC unit, the capacitor is an essential part of the mechanism which both enables the fan to start moving, and also move the motor’s compressor. If the capacitor is faulty, then this can create a problem called ‘hard starting’, where the compressor baulks and shudders on startup, or shuts down rapidly shortly after starting. If your HVAC unit’s motor starts to ‘hum’, then this can also be a sign you have a problem with the capacitor.

Other signs that your capacitor may need replacing would be if it bulges at the top, if the container has a crack in it, or has a leak. Now, to identify what your capacitor looks like involves taking the cover off your AC unit. Unless you have a good understanding of electrical components, we don’t recommend you even go this far, but if you are confident, then trip the circuit breaker between the unit and your main fuse board. Take off the cover, and the compressor should be a tall shiny cylinder. This is the capacitor.

At A&E Air Conditioning and Heating in San Antonio, TX we are keen to write articles that help to provide you with handy tips on operating your HVAC unit that don’t involve asking out an engineer – we are not in the business of trying to persuade you to call us out more than one or twice a year for regular maintenance and servicing. However, in this instance, a qualified engineer is better placed and more experienced to assess the condition of your HVAC unit’s capacitor, and would be able to detect if there is a bad smell or even smoke coming from it.

If you haven’t asked us out before to give your HVAC unit a check over, give us a call and when we come out, we’ll double check the capacitor is working perfectly.