Hello all!

Just installed a used but tested working inducer motor. Part no. JE1DO14N

It's an old Weathermaker SX.

The old one basically fell apart after all of it's mountings came loose. I think it started with some missing fan blades which set the motor off balance and vibrating.

Anyways, the new to me motor will not start at call to heat. However, if I spin it up by hand it revs up and runs beautifully and nice and quiet. I was actually able to get the furnace fully operational by doing this and heated my house up. After hitting thermostat temp, I decided to see if it would start again. Unfortunately no dice. New (used) motor just sat there with a hum and a longing to fire up.

The fact that I can get the furnace up and running by spinning the motor up by hand makes me feel like things like the pressure switch and other such things are functioning as they should.

There is a small capacitor that came with this used motor. Could this be the issue? I tested it and it seems to have the slow build up of charge. I also tried out the old cap with newer motor and it just does the same thing. Doesn't seem to hold a charge though. Going to have my electrical guy test them a bit more at work today but thought I would ask about this here in the interim.

Cap part no: CMKS-X345

Like I said, after spinning it up by hand, the motor runs beautifully.

Any ideas? Any help would be greatly appreciated!

 

Test the capacitor.
If it’s good, you’ll have to replace the motor again.
Hopefully with one that’s not used this time.
If the furnace is old the heat exchanger should be checked and verified it’s not cracked or rotten.

 

I've had good luck with used in the past. Just trying to get through this last stretch of winter. We will be completely replacing the furnace toward the end of summer.

So I have the old old capacitor, and the new old capacitor. Both 3uf+/-5% 250v.

Both seem to function properly in the ohms test. Have a fluke multimeter with auto ranging. Reading goes up and up and up before overloading/getting out of range of the multimeter.

For the capacitance...one shows 2.78uf the other shows 2.94uf. I understand the 2.78 maybe isn't necessarily bad but is 7% out of tolerance, but I assume I should use the 2.94 regardless?

Any other tests I can do with these caps?

What do you think could be wrong with the motor itself if it is indeed the cultprit? I work with many different motors at work and have guys who are good at fixing them (I just swap them out and plug and wire them). Lot's of spare parts and diagnostic tools around to work with.

 

Either cap should work. Try both.
If the motor is sluggish in starting it is either not getting the full 120vAC or the bearings are worn.

 

Well really good news! Did some more troubleshooting when I got home today and found one of the wires connecting to the cap was shorted! Patched it up and furnace is running like a dream!

Thanks for the advice guys!

 

Not quite sure what you found but..... good job.