When our airconditioning is running, I get lots of vibration type noise coming from the Heil furnace and coming through the ductwork. Any thoughts what is wrong? OUr model number is N9MP2075B12B1.

I would check the squirril cage/blower for loosness, clump or dirt, rodent or anything that would throw it out of balance, With Power Off.

I would check the squirril cage/blower for loosness, clump or dirt, rodent or anything that would throw it out of balance, With Power Off.

Thanks much. Very good idea. We will check that out.

I tried to check out the squirrel cage. I can spin the squirrel cage easily. Now it won't start at all. It only will hum. Any thoughts?

Sounds like you lost a bearing in the motor. This would cause the vibration and the not starting. Get a new motor with a new matching motor run capacitor and you should be good to go. I would say try the cap by itself first, but a bad cap wouldn't cause the vibration.

Thanks for you answers. Will try that. Was hoping we could avoid that kind of expense on this furnace that is only about 5 years old but bummer... doesn't sound like it will be low cost. :Thanks again.