Old furnace blower with unknown CFM @ X.X S.P

Old 03-21-13, 08:21 PM
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Post Old furnace blower with unknown CFM @ X.X S.P

I'm currently trying to decipher the CFM @ X.X S.P. on an old furnace blower I picked up.

This furnace blower's frame and wheel were purchased separately from the motor. The company (DETTSON) that manufactured the furnace from whence this blower came from cannot or will not provide me with any data sheets on their product.

This is what I've come up with myself after some research.

My blower frame is a Delhi GT10DD.(T stands for tight, * Tight housings are essentially housings from the next smaller size. There is some loss of performance, sometimes justified by the space savings.)

The specs taken directly from Emerson motor:
Model k55HXRCK-5446
HP 1/2
AMPS 9.2 PH 1
VOLT 115
R.P.M. 1075/4SPD ( Actually only has wires for 3 speeds)

The blowers wheel is 10".

Delhi was kind enough to provide me with a data sheet on their GT10DD frame/blower combo (OEM) and it happens to have a CFM @ x.x S.P. graph but it's for a 1050 RPM 1/2 hp motor.

Canarm was kind enough to provide me with a graph for the G10DD which is actually housed in a regular sized case with no performance loss due to a "T" casing. The graph is for 1075 RPM 1/2 hp motor.

Which factor is influencing the difference in CFM @ S.P. on each graph and by how much?

I recon the 1050 RPM vs the 1075 RPM is having a huge impact on CFM @ x.x S.P. and the actual blower's housing has very little impact.

Any insights appreciated. Thanks in advance.

GT10DD 1050 RPM
G10DD 1075 RPM
Old 03-21-13, 10:52 PM
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Welcome to the forums.

I don't believe the board allows hotlinking to tinypic.
You can post those pics right here on the site.

I looked at those graphs. It was pretty hard trying to read the one.

Are you trying to find a blower for a particular furnace or is this like a science project ?

I'm not an engineer but I don't think the speeds...... 1050 vs 1075 ....... have all that much bearing on the cfm's.

In my opinion the housing and the blower wheel, in particularly the blade pitch, has more bearing on performance than the motor speed.

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