Your AC Blower Motor May Be The Reason You Have No Heat

The AC blower motor stopped working in the HVAC unit below. Here is what happened.

HVAC unit

I have a tenant who called and said: “We have no heat”. It was 18 degrees outside and getting colder. I told her to switch the unit from cool to heat.She called back and said: “Still no heat”. I responded with: “Please switch it to emergency heat.”

She called back again and said: “Now, I smell smoke.”

My response was: “It is okay since the heat has not been turned on this season. It is dust burning off the heat strips. It will go away.”

She called back again and said: “The smoke is not going away.” I responded: “I’ll be right there.”

When I got there, the blower motor on the HVAC unit was not running. I squirted some oil on the bearings, got the motor running and went looking for a replacement blower motor.

This AC blower motor was part of a three-year-old Goodman HVAC unit. The heat sequencer on this same unit failed several months ago for no apparent reason. This unit has a 10 year warranty.

I called my AC guy. Unfortunately, I was unable to get hold of him. I knew I had to get this unit fixed that day because we were having unseasonably cold weather, so it called for plan B, which was to fix it myself.


Here is the process to determine that a blower motor is the problem and then how to replace it.

  • Take the electrical access panel off.
  • Next, remove the panel covering the blower motor.

Things to determine a course of action:

  • Is the blower running? If the answer is no, then check – –
  • If there is voltage to the motor? (There should be a wiring diagram on the inside of the electrical cover.) If the answer is yes – –
  • Turn the electricity to the unit off.

Actions to do with the electricity OFF!!!!

  • Can you spin the motor by hand? If the answer is no, you have a bad motor.
  • Does the motor spin easily? If the answer is yes, maybe the motor is not bad.

NOTE: In my case, the motor was difficult to turn. Since this motor was 1/4 HP (which is a low Horse Power) and was difficult to turn, this meant the motor was bad.


Blower motor replacement:

    • Turn off and disconnect the electrical service.
    • Take the sides of the unit off, as well as the top. Set them out of the way. Remember everything is sharp so be careful not to cut yourself.
    • Here is the blower housing.
    • Remove the blower housing from the unit. This is done by taking out 4 screws.
    • After loosening the squirrel cage blower wheel, remove the AC blower motor from the blower housing.
    • Here are the old and the new AC blower motors. The mounting brackets are the reason to get the factory replacement parts, they fit.

HVAC Unit with reinstalled screws.

HVAC Unit with reinstalled screws.

 

      Pictures of the 4 reinstalled screws that hold the blower housing in place.

HVAC Unit without top and sides.

    • This is the repaired unit minus testing and putting back on the sides and top.
  • Spin the motor by hand to ensure there is no airflow restriction and it spins easily without rubbing.

NOTE: If the unit has not been serviced within the last two years, now is the time to clean it out. Coil cleaner does a wonderful job. Use a bug sprayer, a brush and a garden hose to clean the coils.

HVAC Unit wires for fan.
    • Reinstall the top of the unit, connecting the wires to the condenser fan.
    • Connect all electrical wiring.
    • Before closing the sides, turn the unit on and make sure the unit tests okay.

 

HVAC Unit

 

  • Close the unit.
Getting temperature and air flow readings
Temperature and air flow inside the house at floor register is 199.0 cfm (cubic feet per minute) and 122.3 degrees F. These are excellent readings.The cost to replace the AC blower motor was $162.50. This will vary by region and manufacturer.

Dave Altman
 

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