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View Full Version : Blower motor runs constantly with thermostat in Off position


dcedwa3
Jun 15, 2007, 05:31 AM
The original problem was that periodically the blower motor would stop running when cooling which caused the outdoor unit coil/condenser to freeze up. If I cut the unit off, let it melt, turn it back on, it would run fine for a period. That period could be 3 hours or 3 days.

After taking a look at it, the blower motor in the air handler for the upstairs unit was making a grinding noise, so it was highly likely that the motor was going bad. I replaced the blower motor with a brand new OEM motor and the capacitor. I turned on the power to the unit, the thermostat was still in the "off" position and the blower motor started running. If I turn the thermostat to "cool" the outdoor unit/compressor will kick on, but the blower will only run for about 30 seconds when the thermostat is set to "cool" before it cuts off. This of course will freeze the outside unit and leave me back where I started.

Thinking it was the relay causing the problem, I replaced the time delay relay and sequencer in the unit yesterday. Turned the power back on and the same problem, the blower comes on when the thermostat is in the "off" position. As a test I ran new thermostat wire and a new thermostat which yielded the same results.

Here are the model numbers and part numbers for the replacements that I've done so far:

Split system:
Goodman Air Handler
Model: A24-10
Outdoor Unit:
Goodman 2 Ton Heat pump

Blower Motor:
Part #: B13400313

Air Handler Relay:
Part #: B1370738

Sequencer:
Part #: B1256552


I took pictures of the wiring prior to making any changes so that I wouldn't screw up any wiring. If I match those pictures up with the way it looks now it is exactly the same. It doesn't appear that I have crossed wires or switch some wires around, but it sure sounds like that is what happened.

Thanks for the help.

T-Top
Jun 15, 2007, 08:31 PM
It sounds like to me you put your cooling speed on the normally closed part of the blower relay and when you call for cooling the relay opens killing the blower power. What wires did you use on the blower motor and where are they hooked up? If you turn the cooling off and the blower to on at the t-stat will it keep running? At the thermostat if you turn the cooling on and switch the fan switch on and make it call for cooling will the blower keep running?

hvacservicetech_07
Jun 16, 2007, 09:07 AM
It sounds to me like something is crossed, If you can, post any pictures that you have of the electrical connections.