Help diag. blower motor issue in Lennox furnace

01-21-2012, 02:23 PM	#1
partsace Newbie   Join Date: Jan 2012 Posts: 6	Help diag. blower motor issue in Lennox furnace First, this is a great forum. I have read most of the post for the blower motor issue that I am having, but I can't find a solution. I have a Lennox CB29M-51-2P and the blower motor seems to be dead but is it? After the heat pump has kick on for 30 or 40 seconds, I get both the red and green to light up on the WHITE-RODGERS thermostat. I walk out to the furnace and I hear a medium hum, but the fan is not running. I turned the power off to the furnace and take the door off to expose the blower and such. I turn the unit back on; hear the medium hum and the squirrel wheel is still not moving. I give it a little nudge and the fan starts to spin. BUT, it never runs at the higher speeds; it just keeps running at a low speed and does not move air throughout the house. What do you think the problem is? Scott Model: CD29M-51-2P SN: 5804M02390 3/4 HP | 4.5FLA | 1 PH | 60 Hrz Last edited by partsace; 01-21-2012 at 02:28 PM. Reason: fixed manu name on therostat...

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01-21-2012, 02:28 PM	#2
yuri Hvac Pro   Join Date: Nov 2008 Location: Winnipeg, Canada Posts: 6,609	Help diag. blower motor issue in Lennox furnace bad capacitor. or the motor bearings are seizing. should be able to easily spin it with your index finger ( the one beside the bird ). __________________ "Cut it twice and it is still too short". To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

01-21-2012, 02:36 PM	#3
partsace Newbie   Join Date: Jan 2012 Posts: 6	Help diag. blower motor issue in Lennox furnace Yea, the motor spins just fine. In fact, I need to wait a minute for the motor to stop spinning before I can spin it again... A: On the capacitor, does this give the motor the juice to spin? B: Is the capacitor also in-charge of changing the fan speed or give the motor some more juice to spin it faster? Scott

01-21-2012, 03:06 PM	#4
partsace Newbie   Join Date: Jan 2012 Posts: 6	Help diag. blower motor issue in Lennox furnace Ok. Is it best to replace just the capacitor or both the motor and the capacitor? Last edited by partsace; 01-21-2012 at 03:28 PM.

01-21-2012, 03:27 PM	#5
HvacWiz Member     Join Date: Nov 2006 Location: Northwest Ohio Posts: 286	Help diag. blower motor issue in Lennox furnace Quote: Originally Posted by partsace Also, is a transformer the same thing as a capacitor? No.. it is not

01-21-2012, 03:29 PM	#6
yuri Hvac Pro   Join Date: Nov 2008 Location: Winnipeg, Canada Posts: 6,609	Help diag. blower motor issue in Lennox furnace the capacitor gives it the extra juice to get up to speed and looks like this one and has a rating in mfds like 5mfd/370 VAC or higher. you can buy them at local electrical motor repair shops or Graingers or cozyparts.com for lennox stuff. under $20. Attached Images   __________________ "Cut it twice and it is still too short". To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts. Last edited by yuri; 01-21-2012 at 03:31 PM.

01-21-2012, 04:43 PM	#7
partsace Newbie   Join Date: Jan 2012 Posts: 6	Help diag. blower motor issue in Lennox furnace Mine is 10mfd/370, so that's what I should be looking for, right? Or will a 7.5mfd/370 work? Scott

01-21-2012, 04:45 PM	#8
hvac5646 Part of the Clover Leaf   Join Date: May 2011 Location: NW Burbs of Detroit Mi. Posts: 1,047	Help diag. blower motor issue in Lennox furnace NO! Stick with the OEM rating.

01-21-2012, 04:49 PM	#9
yuri Hvac Pro   Join Date: Nov 2008 Location: Winnipeg, Canada Posts: 6,609	Help diag. blower motor issue in Lennox furnace must be a 10 mfd. __________________ "Cut it twice and it is still too short". To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

01-21-2012, 04:51 PM	#10
partsace Newbie   Join Date: Jan 2012 Posts: 6	Help diag. blower motor issue in Lennox furnace You guys ROCK! I will give it a try. Thanks, Scott

01-22-2012, 04:55 AM	#11
bobelectric Member   Join Date: Mar 2007 Location: 84,Pa.15330 Posts: 898	Help diag. blower motor issue in Lennox furnace Good luck if you have to buy a new Lennox motor.

01-23-2012, 12:42 PM	#12
partsace Newbie   Join Date: Jan 2012 Posts: 6	Help diag. blower motor issue in Lennox furnace We have heat! Thanks Yuri for your suggestions on where to get the part! Went to Grainger and got 2 of them for less than $20.00! Scott

01-23-2012, 03:59 PM	#13
yuri Hvac Pro   Join Date: Nov 2008 Location: Winnipeg, Canada Posts: 6,609	Help diag. blower motor issue in Lennox furnace yer welcome. thats why the damn things don't last, they are cheap. yrs ago an ac capacitor lasted 30 yrs but it was built like a tank, not anymore. __________________ "Cut it twice and it is still too short". To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.