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    sgtaxe's Avatar
    sgtaxe Posts: 4, Reputation: 1
    New Member
    		  
    #1

    Jul 21, 2010, 08:21 PM
    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.
    Stratmando's Avatar
    Stratmando Posts: 11,188, Reputation: 508
    Uber Member
    		  
    #2

    Jul 21, 2010, 08:26 PM

    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.
    sgtaxe's Avatar
    sgtaxe Posts: 4, Reputation: 1
    New Member
    		  
    #3

    Jul 22, 2010, 12:15 PM
    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.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
    		  
    #4

    Jul 22, 2010, 03:07 PM

    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.
    sgtaxe's Avatar
    sgtaxe Posts: 4, Reputation: 1
    New Member
    		  
    #5

    Jul 27, 2010, 04:46 AM
    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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