View Full Version : Gas Furnace Blower Motor
fire514
Nov 1, 2005, 03:55 PM
I have an old Rheem gas furnace. My fan blower motor stopped working. I had Sears order me a new one. The installer walked away, giving up because he couldn't get the old motor out of the housing. I got it out and installed the new one myself. Everything turns freely. I made the furnace turn on and all that happened was an electrical hum when the blower motor was supposed to turn on. I turn the power back off because I don't want to fry the new motor. The electrical connections are the same as the old motor. What else could be going on?! Could there be a relay somewhere that isn't working or something else?
It was hard for Sears to find a motor for me. If there is something else wrong that needs to be replaced, any ideas where I could find the parts?
Anyone have any ideas?
labman
Nov 1, 2005, 04:28 PM
Most likely the new motor may work in place of the old one, but needs something different electrically. See if the motor or any papers that you have for it say anything about capacitor start. The hum and not turn is very characteristic of capacitor start motors without a good capacitor. The old one may not have needed one. I guess the motor could be a dual voltage motor and set for 240 volts. If so, I would have expected it to run on 120, just slowly and heat up. You could also talk to Sears. If they aren't interested in helping, tell them it is defective and you want to return it.
Not a Sears fan here.
fire514
Nov 1, 2005, 04:50 PM
Thanks for responding!
I don't know much at all about electrical work except for running wiring through a house for outlets and such. If the motor needs a capacitor, is that something that I can get and install or is there a different motor that I could get that would have it already incorporated into it?
I'm not an avid supporter of Sears either, but I needed to get someone into my house fast when I was going to be home and that is the name that came to mind. Oh well.
If it is a dual voltage motor, is there a way I can get it to work like normal with the lower voltage? Or would I be better off getting a different motor?
Do you know of a place that I could get parts for my furnace, like the correct motor or anything else I'm going to need?
labman
Nov 1, 2005, 05:44 PM
You should easily be able to make a capacitor start or dual voltage motor work. If it requires a capacitor, Sears should be able to tell how big, maybe sell you the right one. A motor shop should be able to sell you one that would work if you give them the horsepower of the motor. A dual voltage motor should have a diagram showing how to connect it for 120 volts. Don't know a good place to send you for a different motor.
fire514
Nov 1, 2005, 06:00 PM
Okay. Thanks for all of the help! Have to go check things out.
I'll post what happens next... as the motor turns, or doesn't... lol
Answer1PC
Nov 11, 2008, 09:25 PM
Hello
I don't recommend anyone fallow anything that I say here. I am only listing what I would do. If I loose a limb I won't be looking for someone else to blame either.
If I suspect a bad start cap, I find a safe way to spin the motor the instant I apply power. (In the right direction) if the start cap is bad that means it won't start, but will still run if it had some help to start.
If I need a new start cap I KILL (& DISCONNECT) THE POWER find the old one, USE AN INSULATED SCREW DRIVER TO DRAIN THE STORED CHARGE. Then remove it and read the values on the side. As they need to be the same on the new one. Looks don't count except for getting it hooked up & fastened down.
If I can't find it local, I would Google for "AC motor Start Capacitor" In fact if not sure the look of one, go to Google Image and put that in right now to see an get an idea what your looking for.
Because it could also have a Run Cap you need to Google for the "Make Model PDF" to get service manual to know the difference. Almost Vital for the Job.
I guess if in doubt you could change both caps but don't get them mixed up.
fire514
Nov 12, 2008, 06:00 AM
Okay guys... thanks for all the help. I actually forgot to write back on here what happened.
I replaced the electronics and the motor started but was making a strange rubbing sound. It was there before the problems. Not loud, but more like background noise. I always figured it was the normal noise for the motor.
I figured while I had everything apart, I would try to find the cause. It turns out that the squirrel cage was out of round and when it spun, it was rubbing on the housing. So... now that all the electronics are new and it has a new motor and squirrel cage... it runs perfectly. The burn chamber looks really good, so there shouldn't be any more problems with the furnace, I hope! :)
Again, thanks for the help everyone. Now I know how to take everything apart and put it back together again.