Screeching noise from Coleman furnace blower

Reply

  #1  
Old 02-13-16, 03:59 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
Screeching noise from Coleman furnace blower

Hello Forum,

I have a Coleman Presidential II gas furnace (model 7680C) from 1984 that has worked very well until a couple of days ago when I suddenly heard for a few seconds a screeching noise that seemed to come from the blower or motor. I heard the same noise some days later again (and again for just a few seconds).

This morning now I woke up to a cold house (not too cold to be honest; it's already getting warmer here in Arizona) and the furnace was not working. It started working again after pressing the reset button that is located on the left side of the blower, did its job for the next one or two hours and then stopped when the desired temperature was reached.

Is there a way for me as a home owner to lubricate the motor or blower wheel or whatnot (i. e. with the same oil that I also use for the wheel of my swamp coolers)? The furnace is in a rather small cabinet at the back of my house. I would have to "feel" rather then see where to put the oil.

Any help would be appreciated. Thanks.

desertman

PS: I know that it might be time to replace the furnace. 32 years of service is pretty good, even in Arizona. I will look into that later but would very much prefer if I can do it in the summer instead of now.
 
Sponsored Links
  #2  
Old 02-13-16, 04:50 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
I took now some pictures from the motor and blower wheel. I'm attaching two of them - one each from the left and the right side - here.

Question: Could the screw that is visible on the shaft of the ride side picture be an opening for lubrication?
 
Attached Images   
  #3  
Old 02-13-16, 05:17 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
Welcome to the forums.

Unfortunately most blower motors are permanently lubricated and have no provision to add more lubrication. Some people, myself included, have taken the motors out and placed some 3 in1 oil at both ends of the motor....... behind the blower at the motor shaft and in the end cap. It CAN be temporarily successful but there is no guarantee it will help at all.

That screw that is visible on the blower is what holds the blower wheel to the motor shaft.

7680C is a partial model number.

Looks like the motor is OEM part number S1-7966-311P. Must be confirmed.
 
  #4  
Old 02-13-16, 05:52 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
Thanks, PJmax, for your reply. I also thought already that there is nothing to lubricate. normal.

The complete model number of the furnace is 7680C856. It is only used for heating.

I can move the blower wheel easily with my little finger. It does not make any noise when doing it. However, it is not really very easily moving - there is some resistance to it and I don't know whether this is normal or whether the motor is on its way out.

The question is whether it is worth to just replace the motor (which I would dare to do myself in the summer) or whether this would be - given the age of the furnace - a waste of time and money.

I had an HVAC guy from a local HVAC company looking at the furnace about five or six years ago because I thought I should possibly replace it before it fails. The guy looked at the furnace and said immediately: "You don't want to replace this furnace." He then did some checks, including checking the temperature at the registers inside the house, and said again that the furnace would not need to be replaced.

The only repair I had was - about eight or ten years ago - the bi-metal piece that checks the temperature at the pilot light. I think I paid around $90 for parts and labor.
 
  #5  
Old 02-14-16, 03:22 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Received 0 Votes on 0 Posts
Have you established that it's the blower motor making the noise?

If so, replacing the blower motor is a reasonable DIY job.

If you wanted to replace a 32 year old furnace, I wouldn't stand in your way, but replacing the blower motor is likely to be a lower cost way to go, long term.

You live in AZ and have no AC? Tell me more!
 
  #6  
Old 02-14-16, 04:38 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
Thanks for your input, SeattlePioneer. I live in Sedona which is in the summer not as hot as i. e. Phoenix or Tucson. I have two swamp coolers on my house and - since some years - additionally a split unit AC in my office which is a stick-built addition to the house that was not connected to the swamp coolers when I bought the house 12 years ago. Except for some days during the monsoon the swamp coolers work very well. I actually prefer them over an AC because they bring the humidity in the house from around 20% up to about 50%.

I'm sure it's the motor or the blower wheel. I had now several times the screeching noise when the motor came on (or wanted to come on, did not manage due to too much resistance so that the limit switch stopped the motor and had to be reset). Without being an expert I also think that the resistance to move the wheel by hand is too high.

I also looked this morning at the blower wheel when the motor was just coming on and had - when the wheel started to move and was still somewhat slow - the impression that the wheel was slightly wobbling at the outer rim.

What I do not know whether it would be enough to replace the motor or if at the same time also the wheel should get replaced. The wheel certainly looks old (see picture) - but what can go faulty which such a part? (On the other hand: why is this part available on several websites if it lasts forever?)

Motor and wheel cost roughly (incl. shipping) $100 each and I'm confident that I can replace them myself. A new furnace from Alpine costs (incl. shipping) $950, would very most likely need additional parts (like a new roof jack - correct?) and I'm confident that I could NOT replace it myself. Even if I would find a professional to install a furnace that I buy myself (and not from him for a much higher price) I'm sure that replacing the furnace would cost me something between $1500 and $2500.

So I'm asking you guys one more time for your advice. What to replace: motor, motor and wheel, or is replacing these parts simply nonsense and I need a new furnace? Thanks.
 

Last edited by resucami; 02-14-16 at 05:47 PM.
  #7  
Old 02-15-16, 08:37 AM
Member
Join Date: Jun 2002
Location: Northern Minnesota
Posts: 1,649
Received 1 Vote on 1 Post
I have a similar Coleman I installed in 88, not much to go wrong on these. Few years ago I heard a slight squealing when the blower started, few days later it wouldn't start at all. Gas company came and changed the motor in ~30 minutes, pretty easy job.


What to replace: motor, motor and wheel, or is replacing these parts simply nonsense and I need a new furnace? Thanks.
I don't know what could go wrong with the wheel but I guess it's possible. I'd just spend $100 on a new motor then you should be good to go.


PS: I had the gas company do it because I pay for this stupid service agreement so it was free. HA...I've paid enough for this contract to buy 4 furnaces.
 
  #8  
Old 02-15-16, 09:09 AM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
Thanks, Baldwin. I just ordered a motor from Amazon for $93.
 
  #9  
Old 02-15-16, 09:19 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
Normally the blower wheel isn't replaced unless it's bent or out of alignment. Make sure you have some PB blaster or Liquid Wrench on hand as the wheel will be tight on the motor shaft.
 
  #10  
Old 02-16-16, 06:41 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Received 0 Votes on 0 Posts
<<PS: I had the gas company do it because I pay for this stupid service agreement so it was free. HA...I've paid enough for this contract to buy 4 furnaces. >>


Heh, heh! Insurance is expensive. I prefer to carry my own risks when I can reasonably afford to do so.
 
  #11  
Old 02-23-16, 07:03 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
I got the motor, and the PB Blaster should be arriving tomorrow. The motor was most of the last days working but tripped again this morning - I think it's high time to replace it.

Are there somewhere any good instructions how to do this? It looks not very difficult (and I have taken apart and put together again many computers), but still I think it would be good to have instructions. Thanks again.
 
  #12  
Old 02-23-16, 07:12 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
In your picture above..... there should be three bolts or self tapping screws holding the brackets to the frame. After you remove those three the motor and wheel will come out together. Spray the bolt that holds the wheel to the shaft as well as on the motor shaft itself.

After allowing some time for the rust loosener to work try sliding the blower wheel off the shaft. If it doesn't move..... don't pry on the wheel as it will bend and become unbalanced. Take a deep socket, slide it over the shaft and tap the hub to break it loose from the shaft. Then it should just slide off.
 
  #13  
Old 10-03-16, 05:42 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
OK, since it's October and rather sooner than later getting cold at night I thought it's about time to put in the new motor. I got the whole box that contains motor and wheel off, had no problem to loosen the little bolt that holds the wheel to the motor shaft and sprayed the shaft itself with PB Blaster. So far so good.

However, I cannot open the box in which the motor and the wheel are which means that the wheel cannot come out of the box. I guess I have to fiddle the old motor off the wheel and the new motor on the wheel with the wheel in the box. As long as the motor will slide off the wheel that should be possible. Although I would have preferred to have the wheel "alone" for being able to clean it (after 30 years it looks a little bit - really just a little bit - dirty).

But another question is about the power cable for the new motor. It's a black cable and with two wires, one wire is "smooth" and the other one is "serrated". Is it correct to assume that I should put the new smooth where the old smooth was and the new serrated where the old serrated was? (Do you call these wires "smooth" and "serrated"?)

I guess I give the PB Blaster time to work until tomorrow.
 
  #14  
Old 10-03-16, 06:37 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
OMG! The shaft is moving independently from the wheel!

I guess I have the hardest part done but I will wait until tomorrow to put the new motor in. Too many mosquitos at this time of the day.
 
  #15  
Old 10-04-16, 04:11 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
When I went back to the furnace today to install the new blower motor I noticed that the motor shaft was now moving very easily and freely (and not, as it did before, stopping kind quickly due to some resistance). I guess the PB Blaster which I applied to get the wheel off did also do some wonder to the motor as such.

I therefore reassembled (for now) the furnace with the old motor.

When I then switched on the furnace I could hardly believe my ears when I could not hear the motor from my living room (which is wall to wall with the furnace cabinet) and only just a little from my utility room where cold air return opening is. This was very different before; the noise was clearly audible in my living room, and even borderline disturbing when the TV was not on. I also had the impression that now more warm air is coming out of the registers when the blower is running.

I will see whether this works "for good" or only temporarily. The good thing is that I have already a new motor and know how to put it in if necessary.

Thanks for your help, guys. I would not have dared to do this on my own without your input.
 
  #16  
Old 10-04-16, 04:34 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
Unfortunately although the PB blaster has lubricated a dry bearing.... it will not last. That will evaporate with heat leaving you in the same boat.

You're correct with the wiring.... match like insulation markings.
 
  #17  
Old 10-04-16, 07:09 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
"... it will not last."

Good to know. Thanks. I will check how smoothly spinning the wheel is after the furnace has been running for some hours and then probably put the new motor in while it's still warm in the daytime.
 
  #18  
Old 10-05-16, 04:33 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Received 0 Votes on 0 Posts
Sometimes lubricating even a seized up motor will cause the motor to work fine indefinitely. Sometimes it will fail with a few hours of operation and require replacement. If the motor is lubricated per manufacturer's specs, they will usually last for numerous decades.

Most blower motors are replaced because they weren't lubricated.


Personally, I find it worthwhile to lubricate motors on my own furnace as specified by Payne, the manufacturer --- every 5 years. That requires that the motor be taken completely out of the fan housing to lubricate the inside oil cup, but also give s the opportunity to clean and inspect the fan wheel, which is worth doing as long as you have it out.

That takes me about an hour every five years.
 
  #19  
Old 10-05-16, 04:40 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
Most blower motors are replaced because they weren't lubricated.
Maybe because most aren't able to be lubricated ?
 
  #20  
Old 10-06-16, 03:59 PM
SeattlePioneer's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2007
Location: Seattle, Wa
Posts: 5,503
Received 0 Votes on 0 Posts
<<Most blower motors are replaced because they weren't lubricated.
Maybe because most aren't able to be lubricated ?>>


In my experience, blower motors that aren't designed to be lubricated very rarely go bad. They are apparently designed better, and perhaps have a big glop of grease inside that provides lubrication indefinitely.

Most blower motors in home furnaces ARE designed to be lubricated.

I have an ancient Sears Homart furnace installed in 1962. That fan motor doesn't require lubrication, and is still going strong.


By contrast, pretty much NO inducer motors can be lubricated, and it's not unusual to have them fail after 10-20 years. That tends to be a $300-400 repair job including parts.
 
  #21  
Old 11-20-16, 04:48 PM
Member
Thread Starter
Join Date: Feb 2016
Location: USA
Posts: 18
Received 0 Votes on 0 Posts
I finally changed the motor today. It was basically easy - except for the electrical connection. I was not able to get the two wires from the old motor out of the wire harness. See also attached pictures.

I fiddled with all kinds of things from the other side but it was not possible to release the little hooks that are on the pins that are crimped to the wire. In the end I managed to get everything to work with the help of duck tape but I think this cannot be a solution for the next years.

Are there special tools to get the old pins out of the harness?

Or should I buy a new harness? Ace Hardware does not have such a harness. Would an appliance store have it, or should I go to a HVAC company? And if I get a new harness I probably also need new pins for the other cables that are connected to the harness. Can such pins also be purchased?

Attachment 73335
Attachment 73336
 
Attached Images   
  #22  
Old 11-20-16, 05:05 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,207
Received 477 Votes on 447 Posts
The wires aren't normally removed from Molex plugs like that.
There are tools for removing them but you can just cut the wires and make a splice.

I use cap crimps to make the splices.

Name:  caps.jpg
Views: 1364
Size:  7.3 KB
 
  #23  
Old 11-21-16, 04:02 AM
pugsl's Avatar
Forum Topic Moderator
Join Date: Mar 2008
Location: United States
Posts: 8,555
Received 27 Votes on 26 Posts
They make special tools to do that but I have found out they don't work very well. Pete idea is what I usually do. Here are some the top one is one of many I have tried
https://www.amazon.com/s/?ie=UTF8&ke..._sl_9e9dx0qj_b
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: