Air Conditioning Compressor Constantly Running
Our air conditioner's compressor seems to be running long after the fan turns off. Tonight it ran for over 1 hour after the fan turned off. Is this a sign of the compressor about to break or is there something I can do to troubleshoot this problem? The air filter is clean and the unit is dust and dirt free. It's mounted on our roof and we live in Arizona. What is the typical life expectancy of an air compressor?
Answer:
If you are talking about the inside fan (the one in the furnace / air handler) then most likely you have a sticking contactor. Allowing the compressor / condenser to continue running with no 'load' on it from the evaporator (fan) isn't good for it, and will definitely shorten its life. The contactor is inside the condensing unit and generally isn't something that a homeowner should try to fix (high voltages and all that). Time to call a professional. I've seen published numbers for A/C life from eight to 15 years. I've personally had well maintained systems go twenty years or more, but a system of that vintage today is inefficient compared to what is available now. At some point you are better off installing a new system than continuing to have the old one repaired. I would agree that the contactor is easy to replace if you are handy with tools, comfortable with electicity, and know where to get HVAC parts. However, the OP seemed a little confused about the difference between the various A/C components, and I am uncomfortable recommending anything that might be beyond his limits. For the sake of discussion let's assume the OP just misspoke in his question and that he is technically knowledgeable. In that case I would give him this additional advice:: If you feel like you know what you are doing then before replacing the contactor you should check to make sure that when the thermostat's call for cool ends that the contactor coil isn't still being energized. If the contactor remains energized then look for a fault in the low voltage control system. Note: HVAC equipment contains dangerous voltages and a simple misstep can kill or injure you. If you don't know what anything in this paragraph means, don't have a voltmeter, don't know how to disconnect the primary power, or don't feel comfortable doing any of this then call a professional HVAC service person.