WhisperFlo Impeller Downgrade

[boergler]

My pool has an oversized filter and lines, resulting in a very low total head and high flow-rate. My discharge head pressure is nominally 12 psi. I am unsure what my suction head is but probably small since I have a 2 inch PVC pipe for each of three suction lines. That leaves maybe 30-35 feet of water total head resulting in over 100 gpm and a noisy pump. I am thinking to install a 3/4 or even 1/2 hp impeller.

Any advice?

 

[JamesW]

I would go with the 1/2 hp as that should be plenty.

 

[boergler]

I would go with the 1/2 hp as that should be plenty.

That's the way I was leaning. I ordered one and will let everyone know how it went.

 

[JamesW]

Here are the impellers that go to the Whisperflo and how much total hp each impeller requires.

Impeller......Total HP.

073126.........0.95
073127.........1.25
073128.........1.65
073129.........2.20
073130.........2.60
073131.........3.45

The total hp is the rated hp x the service factor.

You can use a motor with more hp than the impeller requires, but not less.

 

[avspin]

Here are the impellers that go to the Whisperflo and how much total hp each impeller requires.

Impeller......Total HP.

073126.........0.95
073127.........1.25
073128.........1.65
073129.........2.20
073130.........2.60
073131.........3.45

The total hp is the rated hp x the service factor.

You can use a motor with more hp than the impeller requires, but not less.

I have a 1HP (011513, WFE-4) and upgraded to motor to the 1 1/2 hp. a few years ago. Pentair told me to switch out the 073128 for the 073129 which is in the parts diagram for the WFE-6, 1 1/2 hp motor. Which has been working fine.
But what you wrote says otherwise unless there is true HP rating.
Just want to understand.

 

[JamesW]

The true hp is the hp x the service factor.

For example a 1.0 hp motor with a 1.65 service factor has a total hp of 1.65.

A 1.5 hp motor with a 1.1 service factor also has a total hp of 1.65.

Both of these motors are the same and interchangeable.

A 1.5 hp motor with a 1.47 service factor has a total hp of 2.2.

 

[avspin]

Where do you find the service factor?

 

[JamesW]

Where do you find the service factor?

It's on the motor label S.F. or service factor.

 

[JamesW]

Magnetek Century 1.5 HP Square Flange 56Y Up Rate Motor - B2854 - INYOPools.com

Century 1.5 HP Square Flange 56Y Up Rate Motor - B2854

www.inyopools.com

 

[avspin]

Got it! Thanks, sorry to side track the thread.

 

[boergler]

I would go with the 1/2 hp as that should be plenty.

I got it upgraded, and I'm glad I went with the 1/2 hp. It is very quite and now and still has lots of flow. Pump discharge pressure is now about 12 psi. The motor demand has dropped from about 2.3 kW to about 1.6; I think I have a pretty inefficient motor. Nonetheless, it will save money on my bill too.

Thank you for the advice.

 

[JamesW]

Good job. Thanks for the update.