Furnace breaker trips instantly

Problems related to residential installations.

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heatseeker
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Joined: Wed Jul 06, 2011 9:10 am

- Furnace breaker trips instantly

Post by heatseeker » Tue Oct 18, 2011 9:27 am

a shorted motor.

heatseeker
Most Valued Contributor
Posts: 542
Joined: Wed Jul 06, 2011 9:10 am

- Furnace breaker trips instantly

Post by heatseeker » Thu Oct 27, 2011 1:49 pm

Not shorted wires, shorted motor, which means you have to ohm out the motor with ohmeter. Good luck.

Freon
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- Furnace breaker trips instantly

Post by Freon » Fri Oct 28, 2011 3:19 pm

"...Goodman furnace breaker immediately trips." I will assume this is not a heat pump system with heat strips in the furnace. If you have the thermostat set to OFF and apply power to the furnace, does the breaker trip? If the breaker does trip then it seems the furnace parts are not the cause. With the breaker off at the main circuit box, check every connection for the 120 volt line from the breaker to the furnace.

With the thermostat set to OFF and you turn on power to the furnace and the breaker does not trip, call for heat and tell us how fast the breaker trips. If it's instantly, then possibly something is wrong at the furnace. Check the control board for signs of arcing... black marks on the printed circuit board.

If the motor is the problem, here's a simple way to determine it. Turn off power. Follow the motor wires to where they connect to the furnace/furnace control board. There should be a molex plug and you should be able to easily disconnect the motor from everything. Make copious notes how this plug is connected so you reassemble it correctly. Now turn on the power and see if the fuse blows. If it doesn't your motor seems to be the problem. Take it to a motor shop and hope is may only be the run capacitor, if it's PSC motor.

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