Gas and Oil Home Heating Furnaces - American Standard Freedom 80 Blower Problems
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tferguso
11-16-08, 03:58 PM
Two nights ago the blower motor on our American Standard Freedom 80 stopped running. From reading about this type of problem online, it seems like it's something in the circuit board, perhaps the blower relay. I'm looking for help to
1) confirm my diagnosis, and
2) figure out where I can get replacement parts.
Some details:
The full model number is AUD120C954J1. This unit has been installed for a long time (about 7 years), so it shouldn't have anything to do with wiring, gas supply, etc. since those haven't changed.
The blower will not run when furnace gets a call for heat, or a "call for cooling" (don't know if that's official jargon or not), or when the "fan" switch on the thermostat is set to on. However, the blower motor will run if I connect it directly to 120V AC, so I know the blower motor works. Lot's of clicking happens after the call for heat (or A/C), at about the right time (there was always a little delay between when the thermostat clicks and the fan starts when it did work), but the blower never seems to get any power. Using a VOM, I checked the leads on the circuit board when I had unplugged the fan, and they never seemed provide power (checked them at various times, turning on/off heat, A/C, fan). I know enough to make sure the blower door safety switch is pressed, to make sure the circuit board itself is getting power - that all checked out fine. The circuit board is getting 120V AC as it's supposed to.
Right now, when the unit gets a call for heat, all the clicking happens, then the gas burners ignite, the exhaust fan runs, but then the unit will shut down. I presume this is because it's getting too hot, since the blower motor is not running, and a safety sensor is telling it to shut down.
Here's what I don't know:
1) Is it possible that there is a sensor somewhere that would keep the blower motor from turning on? Something I've overlooked?
2) Assuming it is a relay, or some other component of the circuit board, where (online, or local store) can I buy something like that?
Thanks for any help,
-tom
1) confirm my diagnosis, and
2) figure out where I can get replacement parts.
Some details:
The full model number is AUD120C954J1. This unit has been installed for a long time (about 7 years), so it shouldn't have anything to do with wiring, gas supply, etc. since those haven't changed.
The blower will not run when furnace gets a call for heat, or a "call for cooling" (don't know if that's official jargon or not), or when the "fan" switch on the thermostat is set to on. However, the blower motor will run if I connect it directly to 120V AC, so I know the blower motor works. Lot's of clicking happens after the call for heat (or A/C), at about the right time (there was always a little delay between when the thermostat clicks and the fan starts when it did work), but the blower never seems to get any power. Using a VOM, I checked the leads on the circuit board when I had unplugged the fan, and they never seemed provide power (checked them at various times, turning on/off heat, A/C, fan). I know enough to make sure the blower door safety switch is pressed, to make sure the circuit board itself is getting power - that all checked out fine. The circuit board is getting 120V AC as it's supposed to.
Right now, when the unit gets a call for heat, all the clicking happens, then the gas burners ignite, the exhaust fan runs, but then the unit will shut down. I presume this is because it's getting too hot, since the blower motor is not running, and a safety sensor is telling it to shut down.
Here's what I don't know:
1) Is it possible that there is a sensor somewhere that would keep the blower motor from turning on? Something I've overlooked?
2) Assuming it is a relay, or some other component of the circuit board, where (online, or local store) can I buy something like that?
Thanks for any help,
-tom
Grady
11-16-08, 05:25 PM
The fact you get nothing on heat, cool, or fan, makes me suspect a possible bad motor. If you have a voltmeter & know how to use it, you can check for 120 volts from the board's cooling speed terminal while the thermostat is set to fan on. If you get power, it would seem the motor is the problem.
If you get no power out of the board, you will probably have to replace the entire board.
If you get no power out of the board, you will probably have to replace the entire board.