Blower Motor

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Old 03-16-04, 01:14 PM
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Blower Motor

Blower Motor on gas furnace kicks in for 3 seconds then turns off. Is now 63 degrees. Thermostat set at 65 degrees. Could be a loose wire? Please advise.
 
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Old 03-16-04, 01:23 PM
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depending on age, either a relay on the circuit board or a fan limit switch operates the fan on in heat. does it go off and stay off, or cycle on and off? age, make and model will help
 
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Old 03-16-04, 02:08 PM
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INFO INFO It sure helps us to help you ED
 
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Old 03-16-04, 02:59 PM
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Originally posted by hvac4u
depending on age, either a relay on the circuit board or a fan limit switch operates the fan on in heat. does it go off and stay off, or cycle on and off? age, make and model will help
The furnace is a Lennox G 8 - ID # G8165C - Serial 679

From the late 60's I think.

However, another posting on this website talked about the same problem and he said he moved an indicator back from 110 to 100 or 90. When getting the above info I found it, did the same, and now it's back on and running properly.

Thank you very much for your interest and help. Seems to be ok for now.
 
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Old 03-16-04, 04:24 PM
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Is the air filter clean in the furnace??See info helps What you had is a furnace going into the summer like. You said 1960 on the furnace so you had a standing pilot in the furnace. So lots of time as it warms up a little out side the furnace might come on then the blower then furnace will shut off ,then the blower but that big old pilot light can warm it up just enough for the blower to come back on and off again. You might want to but it back as it was next winter. I hope you held the dial with one hand as you moved the pointers. Most are set for on at 110-115 and off 90 -95. Its all in what feels warm to you.Glad you got it to work ED
 
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Old 03-19-04, 07:05 AM
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3/19/04 Well, that was a few days ago, and guess what, it started cycling on and off again at 4am today. So I shut off the power and turned it off at the thermostat control. Just turned it all back on and the blower motor is running continuously. I set the temperature to 68, it's now 61, and we'll see what happens. Also, there is only one setting for the dial. I lowered it to 90. Doesn't seem to be an "On" and an "Off" setting. If it starts to cycle on and off again what other adjustment could I make?
 

Last edited by Sharp Advice; 04-06-04 at 02:03 PM.
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Old 03-19-04, 07:45 AM
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Push that fan "off "up some not down if the blower turns on and off to much. You did say the filters are clean?????.AQC coil clean ??
Lennox used a Cam-stat fan limit control way back could be you need a new one. Make sure you get the same element length.
Not hard to change turn power off to the furnace mark down all wires ,take it out put new one in. power back on.

ED
 
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Old 03-19-04, 08:18 AM
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Originally posted by Ed Imeduc
Push that fan "off "up some not down if the blower turns on and off to much. You did say the filters are clean?????.AQC coil clean ??
Lennox used a Cam-stat fan limit control way back could be you need a new one. Make sure you get the same element length.
Not hard to change turn power off to the furnace mark down all wires ,take it out put new one in. power back on.

ED
Ed - What is an AQC coil?
 
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Old 03-19-04, 09:12 AM
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DUH sorry darn fingers The AC coil if you have AC there is it clean and is the air filter clean ?

ED
 
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Old 03-21-04, 06:04 AM
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one question I have. Of the G8 model, and it's heat exchanger. many of them has failed w/ a crack. When was the last time you had this check over? I owuld call in and have someone look at it close.
 
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Old 03-21-04, 06:52 AM
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My Two Cents

Hello: caonline

What is not clear here is, the thermostat is set above the room temp. That point noted. But no heat? Or is there some heat?

Burners on? Burners not on? Clarify. Key clue to know to diagnose the problem or did I miss that point???

If the fan turns on and the burners do not, that's one problem.

If the burners turn on and the fan turns on but does not remain on or cycles on and off while the burners remain on, that's another problem.

If the fan blower cycles on and off while the burners remain on, the room would at least get some heat. But no mentioning of that. Or was there and I missed that too? It's a key clue needed to diagnose the problem but lacking far as I can tell.

Moving an indicator is most likely attempting to cure a symptom not get to the cause of the problem. Details need to be know.

Older units usually have a heat sensitive control called a fan on off control. It senses temp in the firebox, turns on when the temp inside the firebox reaches a set temp.

If that happens (fan turns on) but the blower does not remain on, (fan turns off) or either turns off and on or never shuts off after the burners shut down, the problems and causes differ.

We need to know more. Especially what the burners are doing or not doing. Assuming no burners on only fan turning on for no known reasons or never shutting off. Kindly add more details.
 
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Old 03-21-04, 10:40 AM
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Re: My Two Cents

Hello Sharp Advice -

There is heat. The burners are on.

When I set the thermostat above the room temperature, the furnace burners will come on and after a minute or so, the fan will begin to blow the air, but then, it will cycle off while the burners remain on. Then they shut down.

However, if before the fan cycles on I remove the furnace panel and start the blower motor fan belt manually, it runs continuously as it should until the temperature reaches the setting on the thermostat upstairs.

But then, subsequently when the termperature falls below the room setting, and the burners come on, the fan cycles on for just a short time and then turns off. Then it restarts again, and shuts off after a moment. And keeps repeating like that.

Or, as just now, when the blower motor tried to start, it just hummed and then cut off. So I removed the cover, turned the blower moter pully by hand and when it kicked in again after a very short time, it started and is running now as it should.
 
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Old 03-21-04, 11:04 AM
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Hello: caonline

First, I removed the quote in your reply since I find it distracting to reread what I wrote. Hope you don't mind.

In the first paragraph you wrote, that would likely indicate the furnace is overheating and cycling off on the high limit.

Likely but not all causes of overheating:
1)
A restriction in the air flow system would than be likely. Restriction could be in the A/C coils as Ed mentioned.
Full cleaning is than required.

2)
Too many registers closed or dampers closed, if dampers are there in the ducting. Open everything to allow full air flow.

3)
Intake air restriction. Furnature too close to intake? Too many registers closed, open all of them, Etc.

4)
The fan on/off control is defective. Replacement is required.

A)
Motor just hummming, motor defective and or it is over heating. May need oilling of the end bearings, pulley bearing if any, or the cage bearings need oiling and or replacement of either or all parts, depending on condition and age of any or all parts.

Your next to last paragraph, fan cycles on and off, defective fan switch or defective motor likely since the burners remain on.

Last paragraph. Starting motor by hand indicates motor starting problem. Motor defective, rebuilding or replacement needed.

Hope this all helps more.
 
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Old 03-21-04, 11:41 AM
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If the coil and filter are clean Im still after the motor

When I set the thermostat above the room temperature, the furnace burners will come on and after a minute or so, the fan will begin to blow the air, but then, it will cycle off while the burners remain on. Then they shut down.
Unit went off on limit. Thermal over load in the motor could turn it off.

I remove the furnace panel and start the blower motor fan belt manually, it runs continuously as it should until the temperature reaches the setting on the thermostat upstairs.
Bad capacitor

as just now, when the blower motor tried to start, it just hummed and then cut off. So I removed the cover, turned the blower moter pully by hand and when it kicked in again after a very short time, it started and is running now as it should.
Bad or dead start winding in motor

Like Sharp Advice said also could be bearings----- motor or blower.
ED
 
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Old 03-24-04, 11:37 AM
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[
 

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Old 03-24-04, 11:45 AM
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Originally posted by caonline
I oiled the motor and the fan and the on/off cycle continues.

It seemed to work ok for awhile but now it is back to switching off just after the fan starts turning. I can hear a click, and the motor shuts down after 4 - 5 seconds. I tend to think now that it is the fan limit control switch which may be defective. And will look for one on the internet unless there is there something else I should try first.

Thank you for all you information.

caonline
 
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Old 03-24-04, 12:33 PM
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You dont say ,do you have AC on the furnace? will the blower run on fan on?????Or jump the fan control and see if the motor will run. Before you buy a fan limit control I think its the motor. ED
 
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Old 04-02-04, 05:17 PM
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I think you are right. When the motor turns on the belt will not turn unless I start it by hand, then it runs ok. I have oiled it, but still it has difficulty starting to rotate.
 
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Old 04-02-04, 05:58 PM
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When the motor turns on the belt will not turn unless I start it by hand, then it runs ok.

Do you mean the motor runs and not the belt till you push the belt.. Or when you push the belt the motor will run.

Better yet will the motor start and run with the belt off?????????

Ed
 
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Old 04-06-04, 09:12 AM
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With the belt off, the pully wheel will not start to rotate until it is prodded.
 
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Old 04-06-04, 09:45 AM
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If the motor will run after you push it . Id say the motor needs a new capacitor. make sure you get the same voltage and MFD.

Ed
 
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Old 04-06-04, 10:15 AM
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What is a capacator? Is inside the motor housing?
 
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Old 04-06-04, 11:15 AM
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Is there like a metal bump on the motor?? In this should be the capacitor. It can be black plastic and round. You could have one on the blower some where it would be small silver metal and oval. Be sure and turn the power off first before you work on it

ED
 
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Old 04-06-04, 02:08 PM
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Hello; caonline

If the motor will not start up on it's own, the capacitor may or may not be the cause. Best not to attempt a repair on a capacitor.

Best bet is to remove the entire motor and take it to any local electric motor repair shop in your area. These shops are listed in the phone book.

The shops specialize in the diagnostics of motors and can determine the cause and or problem. Fix the current motor or replace it, which ever is needed.

Once either is done, all you would than need to do is reinstall the motor, new or fixed does not matter. Once installed...problem solved.
 
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Old 04-07-04, 06:05 AM
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Just an additional piece of information: After I prod it to get it going, now it will not shut off. It just keeps running even though the room temperature is above the setting. Even when I turn it to the OFF position on the thermostat, it keeps running until I turn the power off at the furnace.
 
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Old 04-07-04, 07:09 AM
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The fan limit has is on or the fan relay has it on.

ED
 
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Old 04-07-04, 07:13 AM
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Is the fan relay or limit part of the motor? I've located a place in Pontiac where I can take it for repair. Or perhaps replace if defective with a larger two speed motor.
 
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Old 04-07-04, 07:18 AM
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the fan limit and the fan relay are not part of the motor.

Or perhaps replace if defective with a larger two speed motor.
Do you know how to wire in a 2 speed motor into the furnace??

You said old furnace why change to a 2 speed now . Belt drive just change the pulley speed from summer to winter.

ED
 
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Old 04-07-04, 08:18 AM
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How do you do that?

Apparently there is a low speed setting on some motors which will allow you to circulate air continously throughout the house and use less electricity.
 
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Old 04-07-04, 08:32 AM
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The pulley that is on the motor is a variable speed

ED
circulate air continously throughout the house and use less electricity.
you would use more .


ED
 
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Old 04-07-04, 08:51 AM
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How do you vary the speed?
 
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Old 04-07-04, 09:31 AM
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It takes more speed to get the air over a wet AC coil than over the furnace 's heat exchanger.

By the pulley on the motor

ED
 
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Old 04-09-04, 04:25 PM
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Hello All

I'm coning into this a little late but I think I read everything correctly. Most belt drive blower motors don't have capacitors. They have start switches which could give you the problem you are having. If the start switch is stuck, it will try to start on the run winding and not do too well. I also think you have a second problem that won't let the fan shut off. If you have a manual override on the fan and limit control, you may have accidentally set that for constant fan operation. Do you have a white button on the fan control? If so, pull out on it to put it into automatic mode. I would suggest replacing the blower motor.

Ken
 
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Old 04-12-04, 06:26 AM
caonline
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I loosened the belt and oiled the motor and now the blower will turn on and off for the most part, but occasionally the motor will not start, and/or if I start it manually, it will run for 7 - 10 seconds and turn off.

I then turn off the switch at the furnace for 10 minutes and then turn it back on and it starts and runs ok.

Is it the motor? Is it something I can fix?
 
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Old 04-12-04, 08:01 AM
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I've located a place in Pontiac where I can take it for repair. Or perhaps replace if defective
Take the motor over to them and let them check it out.


ED
 
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Old 05-15-04, 12:33 PM
caonline
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Furnace

Finally had a furnace repair company come in and look at it. Turns out he replaced the fan control switch and aligned the belt and now it works fine. I also had him install an electical device which now turns on the water to the humidifier only when the furnace is on instead of all the time, and he showed me how to properly install the furnace filter. So now I'm all set except for the programable thermostat I have in the dining room. He said Hunter's do not always work properly and suggested a Honeywell and some others. Thanks for your help.
 
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