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Old 08-15-2012, 02:13 PM   #1
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Burning smell from AC vents? How do I test to see if it's the blower fan?


I have a plastic burning smell coming from the vents when the AC turns on. The blower fan is not blowing but I can hear the compressor outside running.

When I open up the air handler, I can see that it starts smoking when I turn on the unit from the thermostat, and I can see the blower hum, but not turn.

Being the super intelligent guy I am, this tells me that the issue is a burnt out blower motor.

Can I buy the motor and fan together as one unit to make installation easier? The fan is already rusted pretty badly anyways.

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Old 08-15-2012, 02:16 PM   #2
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Nope. Fan motor and blower wheel will be separate items to purchase.

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Old 08-15-2012, 02:54 PM   #3
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Burning smell from AC vents? How do I test to see if it's the blower fan?


I believe I am going to be purchasing the motor and the fan from Johnstone Supply locally.

Do I also need a fan puller tool or something like that to make this easier? If I recall correctly, I was previously unable to pull the fan free from the motor when I cleaned the fan last year using brute strength (what little I have) and prying methods.
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Old 08-15-2012, 03:09 PM   #4
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Burning smell from AC vents? How do I test to see if it's the blower fan?


You can use some WD-40 or something, even kitchen cooking oil if that's all you have around. You pull the entire assembly out, remove the single screw which attaches/tightens down the wheel/fan onto the motor shaft and drop some lubricant in there. Also drop some onto the end of the motor's shaft, trying to work it's way down.

With an adjustable crescent wrench you grab the motor shaft (there's at least one flat side on the shaft) and then spin the wheel until it's free. Then back and forth spinning the wheel while holding the shaft still, allowing the lube to work it's magic.

DO NOT TAP ON THE END OF THE MOTOR SHAFT, YOU'LL BE FILING OR CUTTING OR BOTH FILING AND CUTTING (NOT TO MENTION SWEARING, LOUDLY) THE END OF THE SHAFT OFF TO GET THE WHEEL OFF IF YOU DO!
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Old 08-15-2012, 03:11 PM   #5
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Thanks Doc.

How do I test to make sure it's the motor that is the issue rather than the capacitor?
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Old 08-15-2012, 03:27 PM   #6
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Buy a new capacitor, change the old one out and see what happens. I can tell you right now it's the motor. They smoke, caps simply go out in an instant.

When changing any permanent split capacitor motor it's always best to put in a new capacitor as well. Change both and be done with it, worry free for years!
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Old 08-15-2012, 05:47 PM   #7
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Burning smell from AC vents? How do I test to see if it's the blower fan?


The fan came off easy.

But now there seems to be another problem.

1. The replacement motor does not have the wings on it that the original did. How am I supposed to mount this thing? I guess I either need a new fan or some kind of mounting bracket.....

2. The original motor only has 2 wires going to a connector. What two wires do I twist these into on the new motor? There are a bunch of wires. I know that 2 will go to something and 2 will go to the capacitor. But I guess none of this matters unless there is a solution to #1.

Thanks Doc





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Old 08-15-2012, 06:10 PM   #8
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Burning smell from AC vents? How do I test to see if it's the blower fan?


There's is mounting bracket. Usually they'll come in three individual wings that screw directly into the motor versus the old one being welded to the motor casing.

Are you certain you have the right motor? How did you determine the correct motor replacement?

What two wires does this new motor have? Pics, please.

I have to go out for a few hours, I'll be back though.
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Old 08-15-2012, 06:29 PM   #9
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Burning smell from AC vents? How do I test to see if it's the blower fan?


I read the part number of the old motor off to the Johnstone Supply counter guy. In retrospect, I should have brought the whole assembly in to him to match up correctly. That would have definitely saved me the second trip I am going to have to make.

Old motor specs:



New motor specs:



Old wiring harness:



New wiring harness:





Side of new motor. I guess the wings I will need to buy screw into here? So I have to screw it directly into the metal? Seems weird to have to do that.
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Old 08-15-2012, 06:51 PM   #10
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Burning smell from AC vents? How do I test to see if it's the blower fan?


No, you want a belly band bracket.
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Old 08-15-2012, 09:44 PM   #11
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Your original motor had 4 mounting legs if I am seeing it correctly in the pic.


They make a belly band mount that goes around the motor. The mount I use has only three mounting legs.


You may have to buy the OEM motor if you donít want to modify the blower housing or motor mount. They may make other mounts with four legs that I am unaware of. I also might be wrong in seeing a 4th mounting leg in your pic.
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Old 08-15-2012, 11:54 PM   #12
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Burning smell from AC vents? How do I test to see if it's the blower fan?


You might want to get the OEM motor for your unit. This one apparently needs quite a bit of rigging. It can work but you'd need the belly band as BT has said. The OEM should come with those wings attached as well as the plug in area.

To use this new motor you'd have to cut that plug off and know which wire was high, med and low on that plug and then wire the new wires from the new motor to the same high, med and low wires that you cut from the plug. Now that plug is trash, unused.

Actually one of those from the plug is a neutral so the old motor was a two speed, I believe. The new motor is a three speed which means you'd need to have a "PARK" terminal on the board to place the unused wire on. And if you don't then you'd simply cap off the unused wire.

Go OEM.
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Old 08-16-2012, 12:14 AM   #13
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Quote:
Originally Posted by Doc Holliday View Post
You might want to get the OEM motor for your unit. This one apparently needs quite a bit of rigging. It can work but you'd need the belly band as BT has said. The OEM should come with those wings attached as well as the plug in area.

To use this new motor you'd have to cut that plug off and know which wire was high, med and low on that plug and then wire the new wires from the new motor to the same high, med and low wires that you cut from the plug. Now that plug is trash, unused.

Actually one of those from the plug is a neutral so the old motor was a two speed, I believe. The new motor is a three speed which means you'd need to have a "PARK" terminal on the board to place the unused wire on. And if you don't then you'd simply cap off the unused wire.

Go OEM.
I was afraid you were going to say that. I hope Johnstone Supply takes returns....

So where do I get an OEM motor locally here in Jacksonville FL as Johnstone Supply does not have this OEM unit?





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Old 08-16-2012, 12:20 AM   #14
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Just so happens I'm a Lennox dealer.

My company is, rather, but even if I weren't I can call Lennox for you and find out how much that motor is and if worse comes to worse I can buy it through my company and if you pay shipping as well as for the motor, send it to you.

I'll need to verify with Beenthere if I'm allowed to help you in this fashion via this forum. I think it's allowed but I'd need to make sure first.

Or you can call any a/c company in your area, give them your unit's model and serial number and ask them if they'll get it for you. All hvac companies can get their hands on it, I'm just not sure they'll just sell it directly to you. They will have to be the ones to install it for liability reasons which brings me to think about what trouble I may get into if I supply the part and you install it and something happens.

I'll have to check with the boss but I'll definitely call Lennox in the morning for you.
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Old 08-16-2012, 12:24 AM   #15
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Burning smell from AC vents? How do I test to see if it's the blower fan?


Quote:
Originally Posted by Doc Holliday View Post
Just so happens I'm a Lennox dealer.

My company is, rather, but even if I weren't I can call Lennox for you and find out how much that motor is and if worse comes to worse I can buy it through my company and if you pay shipping as well as for the motor, send it to you.

I'll need to verify with Beenthere if I'm allowed to help you in this fashion via this forum. I think it's allowed but I'd need to make sure first.

Or you can call any a/c company in your area, give them your unit's model and serial number and ask them if they'll get it for you. All hvac companies can get their hands on it, I'm just not sure they'll just sell it directly to you. They will have to be the ones to install it for liability reasons which brings me to think about what trouble I may get into if I supply the part and you install it and something happens.

I'll have to check with the boss but I'll definitely call Lennox in the morning for you.
Thanks Doc. I hereby release you from all stated and implied liability.

I'd hate to have to call out my AC guy after all this effort I have put in to fixing this problem. And it's such an easy fix..... The fan came off very easily. It's ready to be plugged and played.

PM me the details once you know.

Thanks again.

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