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  1. #1
    Join Date
    Apr 2001
    Location
    Tennessee
    Posts
    210
    I've been working on a Whirlpool furnace that's about 30 years old. I replaced the blower motor because it locked up. Upon putting the new motor in it performed wonderfully while I was on the premises. I throughly checked out all the functions before I left and it was doing great.

    The next day I had to return to my customer because the motor wasn't working causing the condensor to freeze up. After investigation, I discovered that the fan motor would run for about 2 minutes and stop. I checked everything from the motor to the relay to the thermostat and back again and concluded that the voltage at the motor wires would read 120v even when the motor would quit running.

    One more necessary detail... The old motor had the specs engraved on it and everything on the new motor matched except the horsepower. The old motor had 1/2 HP and the new one was 1 HP (everyting else was the same). Wondering if this could possibly be an issue I decided to change the speed of the motor from HIGH to MED/HIGH. When I did the motor ran for 10 minutes without stopping. I let it run another 20 minutes, checked airflow,etc. and Elvis left the building thinking all was well.

    Would you believe they called me today and said the unit froze up and the fan wasn't running. Please help! I'm flabergasted and have to go back tomorrow and try to get my $200 motor working. All the unit has is....
    1. Blower motor
    2. fan relay (working fine because its an old style that you can see the guts of)
    3. Limit/timer
    4. Remember the 120v is present at the motor even when it shuts down.

  2. #2
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    You doubled the HP of the motor and wonder why it doesn't work?


    Well Duh!
    Karst means cave. So, I search for caves.

  3. #3
    Join Date
    Apr 2001
    Location
    Tennessee
    Posts
    210

    It was at the advise of my supplier....

    that i doubled the HP. They said that there is no way a motor as big as that one was with a 5/8 shaft could be 1/2 HP. So why won't it work? Everything else on the motors matched....

  4. #4
    Join Date
    Mar 2004
    Location
    Grottoes VA
    Posts
    5,856
    You are increasing the amprage and the motor is overheating and going off on internal overload.


    BTW, find a new supplier or close your ears when you go in.
    Karst means cave. So, I search for caves.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,760
    Get a 1/2 hp motor, and you'll have a happy customer.

    Without a 1 hp load, the motor is over amping.

    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  6. #6
    Join Date
    Apr 2001
    Location
    Tennessee
    Posts
    210

    Thanks!

    I'm going to try to find a 1/2 HP motor with the 5/8 shaft and put it in today. Thanks for the help guys! I'll let you know how it turns out...

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