I have a heating unit with an Induced draft blower motor that wants to start when the unit calls for heat, but it just hums for about 30 seconds and then the unit shuts down. What should I check out?

I'm not sure if this type of motor use a capacitor but if they do, check it out to see if it is good. Also the small blower wheel may be stuck take a look and see if you can spin it by hand. MAKE SURE THE POWER IS OFF.
You will need a continuity tester to check the capacitor.

Yank the inducer first to see if you have any debris or squatter pests.

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Originally Posted by Frank Almaguer

You will need a continuity tester to check the capacitor.

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Negative. You need to read the microfarads not the continuity. You can have continuity through the cap but the MF's could be too low.

If the motor is humming and then drops out then it is over amping and opening up on internal overload. Either the motor has failed or something is jammed up inside the assembly.

I just replaced an inducer motor on a Carrier furnace, both of the above advisors gave you good advise, one about the motor being burned or shorted, the other about trash being in the squirl cage. One thing though these motors do not have a capacitor.
If your motor needs replacing and it is either a Carrier, Bryant or Payne be prepared to spend some bucks. And I am sure that other models are just as bad.

If you atempt to tackle this job yourself, pay attention on how it all comes apart, it can be tricky getting it back together the right way. Also be very careful with the gasket that is between the motor housing and the firewall of the furnace

Chances are that you will not change just the motor but the entire inducer assembly. On a residential system that is the way it goes... and yes they will be expensive.

Changing entire inducer assembly,, is much easier than trying to replace just the motor,, the extra time it takes to change out just the motor isn`t worth the few extra bucks you`ll spend

Usually you can't get just the motor for a residential system.

I found just the opposite from my distributor, they carry the motor only but not the whole package, This is the Carried, Bryant, Payne distributor, it may be different in this city with distributors of other brands.

I've only found that to be true with commercial roof top units.

I'm hvac challenged and knew nothing until I found this site and started reading. My inducer motor has been noisy for a while now and I've found the same as Letmetellu. You can get just the motor, the wheel and the fan separately [Bryant plus 80]. I did what was suggested on my post for a similar problem and tapped on the pressure switch while the furnace was runnning and it shut down. I ordered an inducer motor and a dual pressure switch that I'll be installing tomorrow... wish me luck!

Good luck

If you are replacing the motor only, I do wish you luck... getting the wheel off the old assembly.

Thanks guys. Sorry if my post turned into a hi-jack, didn't intend it to. I looked for my old post... there's a lot of traffic here! I'm an auto mechanic by trade, so I'll try not to screw it up. Sure don't want to be completely out of heat in the middle of winter. I guess I could let it keep going as is until the ambient temp goes up. The house is staying warm, just keeps flashing code #31 and just doesn't seem to be operating 100%. I will say, after lightly tapping on the pressure switch it has been working better? :confused:

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Originally Posted by KC13

If you are replacing the motor only, I do wish you luck...getting the wheel off the old assembly.

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Which is exactly why I order a new wheel as a rule.