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 Repairing and Servicing Lennox Products
 Repairing / Servicing Lennox Gas Furnaces
 G12 furnace
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walter

8 Posts

Posted - 01/10/2007 :  8:59:34 PM  Show Profile  Reply with Quote
i have a
g12 furnace that the blower will not run.
i have power to the furnace, and the piolet light is lit. the furnace burners light and every thing seems to be fine but the warm air doesn't circulate the house. the problem is the blower doesn't kick on.
what could cause the blower from not kicking on?
the full model number is G12Q3-110-5
thanks in advance for you help
walter

Cozy.Support

5740 Posts

Posted - 01/10/2007 :  10:07:48 PM  Show Profile  Reply with Quote
If you have air conditioning, you probably also have a fan switch on the thermostat to turn the blower on to run continuously. If you cannot turn the blower on at the thermostat, and the fan will not come after the gas burners come on, you probably have a problem with the fan motor or motor wiring. Some motors (not all) in the G12 series also have a run capacitor that could be defective. Not an easy answer here without some voltage measurements.
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walter

8 Posts

Posted - 01/11/2007 :  02:06:21 AM  Show Profile  Reply with Quote
ok thanks for your help so far.
it does have air conditioning and when i turn the blower on to run continuously nothing happens. how do i locate a run capacitor if i have one and how do i test it?
thanks again in advance
walter
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Cozy.Support

5740 Posts

Posted - 01/11/2007 :  07:48:45 AM  Show Profile  Reply with Quote
I did some checking and this model would of had a run capacitor mounted on the front of the blower housing.

Most homeowner's do not have a capacitor checker, but many do have a VOM. You can check a capacitor with a VOM, but it is harder to do, and a little less reliable. The link below has information about how to check a capacitor with a VOM

http://www.repairfaq.org/sam/captest.htm
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walter

8 Posts

Posted - 01/11/2007 :  12:01:19 PM  Show Profile  Reply with Quote
thanks for the help but i couldn't figure out to check it. i am going to buy one and see if it soves the problem. can you give me a part number so that i can order it?
thanks again walter
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Cozy.Support

5740 Posts

Posted - 01/11/2007 :  1:29:35 PM  Show Profile  Reply with Quote
Use the link below to enter your model information and one of the Cozy parts specialists will look it up for you.

http://www.cozyparts.com/Lennox-Parts/locator_form.aspx
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walter

8 Posts

Posted - 01/11/2007 :  1:55:40 PM  Show Profile  Reply with Quote
Thank you!
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MechAcc

1499 Posts

Posted - 01/11/2007 :  5:35:55 PM  Show Profile  Reply with Quote
Side note: You may have to remove and check the motor nameplate. If the motor has ever been changed then the run capacitor may not be the same as the original equipment that the manufacturer installed.

I am not an employee of CozyParts. The opinions that I post are my own.

Please have your furnace inspected annually by a qualified service technician. Have them test the undiluted combustion gases for proper combustion and carbon monoxide production.

Get a good Carbon Monoxide Alarm. Replace it according to manufacturers recommendations usually every 3-5 years. CO concerns are not just for the winter but 24-7. UL approved alarms alarm high. For a low level alarm do a search for CO Experts or NSI 3000 a low level CO monitor.
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walter

8 Posts

Posted - 01/21/2007 :  03:46:50 AM  Show Profile  Reply with Quote
Hi again, I have changed out the switch relay and the run capacitor now and the fan motor still does not run. Could it be the fan motor?
Thanks in advance
walter
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Cozy.Support

5740 Posts

Posted - 01/21/2007 :  06:44:32 AM  Show Profile  Reply with Quote
Have you used a volt meter or test light to see if you even have voltage going the motor? It definitely could be the motor, but it also could be something else. You really need to take some voltage measurements.
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walter

8 Posts

Posted - 01/23/2007 :  8:07:09 PM  Show Profile  Reply with Quote
What will be the best way to take voltage measurements? I have a voltage meter but I donít know what wires to test! Any help would be grateful
thanks again walter
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Cozy.Support

5740 Posts

Posted - 01/23/2007 :  8:38:05 PM  Show Profile  Reply with Quote
I am a little reluctant to give much advice here, because I don't know your skills. If you do not understand what I am describing, you probably do not have enough skill to troubleshoot this situation, and you probably should hire a Lennox dealer to look at it for you.

In the heating mode, the power travels from the fan side of the fan/limit control, through the normally closed side of the fan relay to the heating speed tap on the motor. You simply need to confirm that there is power to the line side of the fan switch, that the switch is closing, and that the power is continuing on through the normally closed side of the fan relay to the fan motor heating speed tap.

If you do not comprehend the instructions here, or do not know how to safely use a volt meter, for your own safety, you should hire someone else to look at the furnace.
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walterdaman

11 Posts

Posted - 02/17/2007 :  5:54:37 PM  Show Profile  Reply with Quote
Thanks for the advice so far. I thought based on the input so far a malfunctioning blower motor was the problem.

When I hooked up the wires for the new blower motor the blower motor turned however smoke started coming out from the new blower motor housing and I smelled a burning smell coming from the blower motor. The smoke started coming from the blower motor after about 30 seconds of being connected.

I have looked at the wires and none of the wires looked like they were damaged.

What could be the cause of the smoke?
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Cozy.Support

5740 Posts

Posted - 02/17/2007 :  6:07:52 PM  Show Profile  Reply with Quote
You most likely have it mis-wired. You most likely have a ruined motor as well. You might luck out, but I doubt it.



Cozy.Support does not provide a diagnosis for users of this forum. We do, however, try to provide information that will help servicers arrive at their own diagnosis.

Once you know what part you need, you can contact the Cozy parts department by using the link below
http://www.cozyparts.com/Lennox-Parts/locator_form.aspx

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walterdaman

11 Posts

Posted - 02/17/2007 :  6:29:44 PM  Show Profile  Reply with Quote
I am almost certain I re-wired the blower motor the same as what the old one was.

Would you have the wiring diagram or could you suggest where I could get the wiring diagram so I can check to see if the wires were correctly wired to begin with?

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Cozy.Support

5740 Posts

Posted - 02/17/2007 :  6:46:53 PM  Show Profile  Reply with Quote
If you will post your complete model number, I will see if I have it. Make sure you are not energizing two speeds at the same time.. if you are, it won't last long.



Cozy.Support does not provide a diagnosis for users of this forum. We do, however, try to provide information that will help servicers arrive at their own diagnosis.

Once you know what part you need, you can contact the Cozy parts department by using the link below
http://www.cozyparts.com/Lennox-Parts/locator_form.aspx

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