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Discussion Starter #1
I'm trying to figure out the cfm rating for a central air unit fan. this unit was given to me and has no paperwork. There is no manufacturer printed but i have a model of B20-36 also a b/m number 8041-1-3a it is 6.3 amps and 1/3 hp. the output is about 14x 11 3/4 what i believe is called a centerfugal(sp?) fan, blades are about a foot tall. any info anyone can provide is greatly appreciated even guesses for manufacturer would be great.
Yes i know this is a strange question and not the right way to do things.
 

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I'm trying to figure out the cfm rating for a central air unit fan.
it is . . .1/3 hp.
the output is about 14x 11 3/4
blades are about a foot tall.
CFM is related to power draw and duct size.
Look in paper or Web catalogs that do show CFM for units comparable to yours in size, fan config. and power draw. This will get you within a few percent of what your unit does; they all have to follow the same laws of physics. You want "the fan curve".
 

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The amp draw you posted, is more amps then a 1/3HP motor draws weather its a 120volt, or 240volt motor.

In the 3/4HP range for a 120volt motor.
Close to 2 HP for a 240volt motor.
 

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Sounds like it might be an exhaust hood fan, typically found in a restaurant.

Does it look like this?

 

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Discussion Starter #5
Thank both of you for your speedy replies. plate says 115v, of course the numbers don't make sense (story of my life) but i assure you that is what the plate says. amp 6.3 min fuse 8a (i'm running 12ga to it anyway) any thoughts to who made it?
 

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Heh, well when you said the blades were 1' tall, I remembered that these units have blades that are tall ;) At least the one I had in my shop for awhile.

I will admit, I've never seen one used in a house thought. :)
 

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Discussion Starter #10
sorry i don't think i was quite clear on what i'm talking about, the correct term is air handler. the indoor unit, all i can find is complete air handlers with the fan and evap not just the fan in a box. sorry that centrifuge thing probably threw everyone off. american standard, trane, lennox, carrier none of them have anything specific on their site any direction i should go to find just a fan and it's specifications?
 
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