# Furnace Inducer Motor Won't Shut Off & Not Heating to Set Temp.



## yuri (Nov 29, 2008)

Take the bottom door off the fan compartment and then press the door switch in and put metal foil duct tape on it to keep it in the ON/closed position.

The next time the furnace acts up: Slowly and carefully remove both doors w/o banging the furnace. Then gently tap the circuit board with the handle of a screwdriver. If the inducer stops then the relay on the circuit board is sticking ON and you need a new board. Most likely that is the problem.

Remove the tape on the door switch when finished. If you do not tape it closed it will kill the power when you remove the door.

Try supplyhouse.com or americanhvacparts.com for the board.


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## beenthere (Oct 11, 2008)

So its only the inducer that is running, not the inducer and blower/fan.

If so, then need to find out if the fan is shutting off in mid cycle. Due to the motor maybe being defective, or its capacitor being weak.


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## user_12345a (Nov 23, 2014)

Disconnect the wire connected to W a the control board and see if the inducer stays running.

If it doesn't, problem is internal to furnace.

With the inducer running during a call for heat, check the ac voltage drop across the pressure switch -> should be just around 0v.

24v +/- and the pressure switch is open. A manometer should be put on it to see if it's bad or something else is wrong.

It's not the inducer or it's capacitor because it was just replaced.

If your furnace is high efficiency check the exhaust/intake pipes as well as the drain line and trap. Blockages will cause pressure switch to not close.


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## YorkP2UDD (Nov 10, 2017)

Thank you to all that have responded. Any and all help is welcome & greatly appreciated!

Yuri, 
We tried taping the switch in the on/door closed position, tapped on and around the circuit board and the inducer did not shut off. We did hear a couple clicks though and then a red light would flash once. According to our manual it indicates that there is an internal problem. We did this several times and got the same result. We also find that during the call for heat the igniter will glow and there will be some clicks by the control board. The igniter will glow for a little bit and then go out. Every other click the red light flashes once and this sequence happens 4 to 6 times before it lights. Then it will send heat for about 2 to 5 minutes and shut back down - inducer motor running the entire time and never shutting off. The inducer is on as soon as we turn the breaker on and the only way to turn it off is to turn the breaker off or turn the thermostat to off. It did also turn off when we tried what user_12345a told us below...

user_12345a, 
We disconnected the wire to W and then the inducer DOES shut off. That would be the wire that goes to the thermostat. While the furnace is running & blowing heat it reads 0v. We could see condensation leaking out from around a screw and trickling all the way down over the control board to the floor & could hear it gurgling so we removed the pipe and had quite a bit of condensation come out. Nothing new happened after emptying it out of the pipe. There is no condensate trap. How do you keep that buildup from happening? 

beenthere, 
It is just the inducer that is saying on, not the blower fan. This is the part that the tech. originally said was the problem so we paid for the new inducer, he hooked it up, and we are stuck with the same issue of it not turning off. Fan is not shutting off mid cycle. Tech. told us it's the thermostat and we should get one that has batteries. We have now purchased 2 more thermostats and haven't had any luck. So far we have spent almost $600.00 and still have no heat and don't have anyone else to call.


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## yuri (Nov 29, 2008)

It sounds like the board is faulty and keeps sending a signal to the inducer fan relay to energize it. Plus it is giving a internal error so I think it is shot.

Usually if you have a sticking inducer relay shutting off the breaker and turning it on does not stop it as it is mechanically stuck on.

I would replace the board.


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## beenthere (Oct 11, 2008)

YorkP2UDD said:


> beenthere,
> It is just the inducer that is saying on, not the blower fan. This is the part that the tech. originally said was the problem so we paid for the new inducer, he hooked it up, and we are stuck with the same issue of it not turning off.
> 
> Good thing you use a better auto tech then HVAC tech. The inducer can only run if the board is sending 120 volts to it. So the inducer can't be at fault for it always running.
> ...


Take a pic of where all the low voltage wires are connected on the board. Then remove all of them. And see if the inducer still runs all the time. If it does, then you have eliminated the thermostat and thermostat wires as being the problem.


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