draft inducer runs furnace won't kick in - http://www.hvacmechanic.com/ Forums
Original message
| konan
 |  "draft inducer runs, furnace won't kick in"
, posted Wed 25 Oct 21:19:  
Last night we woke up to a hot metal smell and chilly air. We traced it to the furnace (a Lennox)and after pulling off the top panel discovered the draft inducer fan motor to be very hot. I took it off to make sure it wasn't blocked and spun freely. 24 hours later I put it back on and turned the power to the furnace back on. The draft inducer seemed to run fine but the furnace never fired and the furnace blower fan never kicked in. After about half an hour of just the inducer fan running I shut it off. The inducer fan moter was warm to the touch. (I checked the thermostat and confirmed it was calling for heat.) Anybody have any thoughts on what my problem is? Thanks for any help and your time.
[this message was edited by konan on Wed 25 Oct 21:27] |
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| Konan
| "Re(1):draft inducer runs, furnace won't kick " , posted Thu 26 Oct 10:19
I think I found one of the problems. When I reinstalled the inducer blower I neglected to hook up the tube to the pressure switch. Thats why the furnace would not turn on. Da!. I suspect I still have a partially burned out inducer motor. Thanks for the tip on the 5 year warranty I think I can use that. Thanks for your help to those who responded.
L Philip Nelson
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| bruiser29853
| "Re(1):draft inducer runs, furnace won't kick" , posted Thu 26 Oct 05:43
I have seen the port on the inducer assembly get plugged with trash. Remove the hose from the pressure switch and blow through it If it is plugged it wont let the switch close.
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| Freon
| "Re(1):draft inducer runs, furnace won't kick" , posted Wed 25 Oct 22:41:
Check there's nothing blocking the flue that would make the inducer work harder. Next you may need to oil the inducer motor bearings. Try and run some 3-in-1 oil (blue label) down the shaft. You really need to disassemble the motor to do it right when you get a chance.
[this message was edited by Freon on Wed 25 Oct 22:42] |
| | acefurnacefxr
| "Re(2):draft inducer runs, furnace won't kick" , posted Thu 26 Oct 06:58
quote:
Try and run some 3-in-1 oil (blue label) down the shaft. You really need to disassemble the motor to do it right when you get a chance.
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These motors cannot be lubed, and should NEVER be disasembled by a home owner. Look on the main board for a fault code, i am betting that you have a pressure switch fault due to a blocked drain, intake or a defective inducer motor. Remember ALL lennox high effecency units have a 5 year pts warrenty.
My spelling sucks thats why I am not a teacher.
22 years of running HVAC service calls Man I have seen it all.
I belong to a union
I also belong to a gym a campground and Triple A.
I may tell you whats wrong but its my job to fix it not yours.
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| | Freon
| "Re(3):draft inducer runs, furnace won't kick" , posted Thu 26 Oct 13:49
Since the OP stated "...Last night we woke up to a hot metal smell and chilly air. We traced it to the furnace (a Lennox)and after pulling off the top panel discovered the draft inducer fan motor to be very hot...", it seemed something was wrong with the motor.
Many times a motor will overheat due to excessive load or poorly lubricated bearings. Since most inducers have small squirrel cages the will usually not provide excessive loads due to 'slippage' at high static pressure, I thought he may have a dry bearing. Many motors, whether using sleeve or ball bearings, can be lubricated by running oil down the shaft. Granted you only lubricate the front bearing but that's the bearing with the greatest load so it usually is where the problem is. And I hesitate to assume a homeowner isn't intelligent. Many homeowners are very capable of disassembling and reassembling a motor.
If the friction is enough so you smell hot metal then there's a good chance the motor isn't generating the rated hp needed to activate the pressure switch. All the cleaning and switch replacing won't cure the underlying cause of the lack of pressure. Only a new or rebuilt motor will...my 2 cents.
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