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-   -   No Blower in on or auto (https://www.askmehelpdesk.com/showthread.php?t=490631)

  • Jul 21, 2010, 08:21 PM
    sgtaxe
    No Blower in on or auto
    I have a package unit outside. The ac stopped working. TStat seems to be working fine.

    In the past, I replaced the control board 2 years ago, compressor fan motor 3 years ago along with all 3 capacitors.

    There is no fan in fan or auto modes. The squirrel cage spins nicely by hand and checked power, it is there at the motor with the tstat in fan mode, but no spin. Power not flowing through the contactor ( not plunged in).

    I replaced the transformer, because that is often the problem with no fan? Replaced the contactor because the resistance was less than 10 ohms between the low voltage sides? No change

    The control board has a 5amp fuse which I reseated and checked.

    There is no power between R and C. Am I looking at a board change again? Thanks in advance.
  • Jul 21, 2010, 08:26 PM
    Stratmando

    If you have voltage to the motor and it doesn't spin, don't mess with transformer, thermostat or anything, the problem is at the motor.
    I would suspect Transformer, or fuse if I got NO response ftom thermostat.
    Also see if 240 volts is present on line side of contactor, and 240 volts on load side when energized.
  • Jul 22, 2010, 12:15 PM
    sgtaxe
    There is power on the line side, but the contactor never energizes.

    Quote:
    Originally Posted by Stratmando View Post
    If you have voltage to the motor and it doesn't spin, don't mess with transformer, thermostat or anything, the problem is at the motor.
    I would suspect Transformer, or fuse if I got NO response ftom thermostat.
    Also see if 240 volts is present on line side of contactor, and 240 volts on load side when energized.
  • Jul 22, 2010, 03:07 PM
    hvac1000

    The contactor is energized by a 24 volt signal circuit. Break out the good old voltage meter and start back tracking the circuit to find the problem.
  • Jul 27, 2010, 04:46 AM
    sgtaxe
    OK. I started checking power and found that only 1 leg of the double pole contactor was getting power. So I replaced the circuit breaker. Now the Compressor and its fan now work but still no blower motor. I checked power at the blower and it had 110v, 27v, 18v at the com, hi and low connections. I thought that it was the blower that was bad now until I found that it was supposed to be 240v. So I ran a jumper to the fan from the board and the fan powered up. I then took the board off and noticed a big burned arc spot on it. I replaced the board and now all is well.

    Thanks

    Quote:
    Originally Posted by hvac1000 View Post
    The contactor is energized by a 24 volt signal circuit. Break out the good old voltage meter and start back tracking the circuit to find the problem.

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