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Problem: Why does my air conditioner fan motor keep burning up?

troubleshooting air conditioners and heat pumps

Question: In May I started to have some problems with my outside ac unit. My fan stopped running but I could get it back running by spinning the blade when it hmmmmmed. Blade was easy to spin Called an AC Company to see what was wrong They said the fan motor was bad and put in a new fan motor and oval capacitor.
But didn’t replace the dual capacitor said it didn’t need to be replace it was good. Ran good and cooled down the house good for about a mouth or so but started having the same problems. My fan stop running I could get it back running by spinning the blade when it hmmmmmed. Blade was easy to spin, but motor was hot to the touch
Ac company came out again said it was a bad new motor. Company put in a new fan motor and oval capacitor but didn’t replace the dual capacitor said it didn’t need to be replaced that the capacitor was good. Ran good and cooled down the house good for about a mouth or so but started having the same problems. My fan stopped running but it’s hard to spin now and takes a couple of tries to spin when it hmmmmms. The motor was hot to the touch. Now the fan motor won’t start to spin by me spinning it at all. It is too hard to spin. Note: The motor is still hot to the touch. What could be possible wrong with my unit? Why does my fan motor keep burning up?

Answer: Hi! I am so sorry to hear that you are having all these problems with your fan motor. There are several things that can cause a fan motor to go out prematurely. I will list some of them below then you can assess whether any of these might be causing your fan motor to go out so often.
1. Installing a universal fan motor that is not matched correctly with the right RPM or horsepower to power the fan blade. Motor not matched to the diameter and pitch of the fan blade. Motors should be matched (RPM, Horsepower, Amps) with the fan blades or it will over-load the motor and the motor will fail soon.
2. Having a fan blade that is off-balance and causes vibration to the motor and unit. A new balanced blade would be best.
3. Installing a fan motor and capacitor where the capacitor does not match the specs on the label of the fan motor. The fan motor capacitor should match the specifications on the motor label.
4. Installing a fan motor where lots of moisture is present like from a leaking gutter or down spout. Water pours on to fan motor when it rains or when snow melts.
5. Not having the rain shield installed (when required) or leaving drain plugs open where water and moisture can get into the motor. Some motors have rain shields to prevent water from getting into the motor. Many universal motors do not have rain shields, but have drain plugs that can be opened or closed depending on how the motor is installed, horizontal, vertical, shaft up or shaft down.
6. Improper wiring. Where the motor is not wired according to the label on the motor.
7. Improper rotation of the fan blade. With the fan blade spinning in the wrong direction the motor will not load and it will burn up over time.
7. Grass, weeds, plants or children that stick into the fan blade path and stop or impede the fan motor when it is running.
More than likely the HVAC company you had installed a universal fan motor. Many of these motors use an individual capacitor and this is why they did not hook into your existing dual capacitor. They probably are using the dual capacitor for the compressor only and the fan motor they installed has a separate single capacitor. I am just guessing. I am thinking that probably number 1 is probably the problem. That is why we mostly sell OEM fan motors so they will be matched with the fan blade and the customer has an easy time with the installation. If you would send your unit’s model number I will try to find out which OEM motor fits your unit. Our support email address is: support@arnoldservice.com. We will be glad to try and help you out!  Steve Arnold

Please comment below if you would like to add to this post or email us at: support@arnoldservice.com

4 thoughts on “Problem: Why does my air conditioner fan motor keep burning up?

  1. I have the same issue before, the AC guy didn’t explain much about it. Thanks for sharing.

    1. Thanks! I hope this page helped you find out what might be wrong that is causing your fan motor to burn up. Hope you have a blessed Memorial Day weekend! Steve

  2. Is it dangerous when pilot gos out but still can fell heat.wat drawing heat no pilot lit?

    1. Hi Ms. Perez! If your pilot goes out during a heating cycle you will feel some heat come out of the furnace until the furnace heat exchanger cools down. This is not dangerous because most pilots that I have seen have a safety device called a thermocouple that will not allow the main gas valve to open if the thermocouple does not sense the heat of the flame of the pilot. So if the pilot flame is out the thermocouple will not allow the main gas valve to open until the pilot is lit again and has a flame. I hope that I have answered your question. I hope you have a great day! Steve

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