I need some help with a non-working furnace in Colorado.

The furnace is an 1988 “Inter-City Products” induced draft furnace in our crawlspace. I thought I smelled a slight burning smell from a vent a day or so before the furnace stopped working. A day or so later, I noticed there was no heat. I trudged down into the crawlspace and found the furnace lights and heats up but is not blowing air. I opened the blower door and discovered that the blower motor is not turning. I oiled the motor with WD-40. The motor turns a few revolutions, then stops. The squirrel cage spins, but not very freely.

I called for service, in case there was something wrong besides a bad motor. The technician diagnosed a bad motor and wanted $700 or so to replace motor. He told me the furnace motor is not original, and neither are the gas jets, as well as some other parts, so the furnace is on its last legs. He said I should consider replacing the furnace. I agreed, but decided that, in the meantime, since we had no heat and were using electric space heaters around the house, to replace the motor myself, and then look into buying a new furnace.

I bought a replacement motor from a reputable local shop and replaced the motor. I turned on the furnace and ran the startup sequence and the draft inducer motor started, the spark ignited at the electronic pilot, the furnace lit, the exhaust vent from the inducer motor heated up quickly, and then the flameout switch tripped and the furnace stopped.

I called for repair and a second company came out to diagnose (I couldn’t get the first company to return quickly enough.) The second company’s technician diagnosed that the blower motor is not turning quickly enough. He ran the motor from a separate power source and said the motor is going 300 rpm instead of 1750 rpm.

I go to the place where I bought the motor and they tested it and said it is running fine at 1750 rpm. They said maybe it’s the blower cage causing the trouble.

I removed the entire blower cage assembly. I saw no obstructions. It needed to be cleaned, but it’s not horribly dirty.

I don’t want to spend lots more time and energy and money on this. Besides, my wife hates the cold and I’m looking colder and colder to her. I’m going to replace the furnace, but I would like it to run until we decide what company’s going to install which furnace, because I hate to think how much electricity we’re using with those space heaters. Luckily we’ve had milder and sunnier weather this week, but it threatens to get much colder.

Any ideas? Thanks!

-Bob

You should be able to easily spin the squirrel cage by hand. If its bearing are bad, and dragging, the motor is not going to be able to turn it. You must get some lube in the bearings for the fan. Chances are they are sealed for life, without any easy way to lube. You may have to slide the shaft out of sleeve bearings and apply grease by hand. With sealed ball bearings, drill a hole in the seal, or remove it completely and add grease or oil.

If the motor now turns the fan OK, you have bought yourself some time. You may have to keep adding grease or oil to nurse a bad bearing along. You should be able to judge whether the fan ''sounds right'' like it did before.

With a new motor, you might consider new bearings for the fan if they are the problem. If the heat exchanger is sound, and the furnace isn't an inefficient older design, you might keep it having invested in a new blower motor.

Code may forbid a fuurnace in the crawl space now. A new furnace may have to goelsewhere. You are allowed to repair an old one.

Hi
My furnace blower motor runs for 2-3 minutes, Then quits, help

Pat