We built our house four years ago. We set up bi-annual inspection of our HVAC from the beginning. We were told this year that when they originally installed the system, the wrong capacitor was put in both units so they replaced them less than a month ago. This weekend (Friday night) the upstairs unit was making a horrible sound outside and was not cooling. They came out and found nothing wrong. Not one hour later I heard the same sound outside. I told my husband and he heard it the next morning. We called them back and he came out and said the fan motor was not working and needed replacement. Luckily, that is under warranty, but they want to charge for the labor to replace it. I don't have a problem with this but I want to make sure that this isn't going to happen to the other unit as well. I want to make sure that if they would have installed the proper capacitor size for the unit would it have prevented the burn out of the motor after only four years of use?

Tough one. I won't guarantee that the wrong cap ruined the motor. However, I will say that an incorrectly sized capacitor can indeed shorten the life of the motor. I have seen motors with the correct caps burn out in less than a year, but a motor with a mismatched capacitor is never a good thing.

Thank you for your response. I spoke with the manager of the company and he said that in no way would this be possible. He said that some motors just fail. I definitely plan to get a home shield warranty before my warranties start to expire to prevent such high replacement costs.

I agree, some motors do just fail. However, a correctly sized capacitor does play a large part in correct operation and longevity of motors. Otherwise, they wouldn't make so many different sized capacitors, there would just be one size. Of course, they are going to cover their backs, as they don't want to pay for a new motor and labor to install it. Most likely the cap wasn't the issue, but it is always a possiblitly. Glad its under warranty, at least parts. I would bet they install a new motor and new matching capacitor at this point. Good luck and I hope the new motor last for years to come.