Going to downgrade a waterway plastics impeller

[cfherrman]

I got a 4 hp 2 speed 220v waterway plastics hi flow pump that will have way too much flow for any kind of sand filter I could afford. My plan is to downgrade the impeller to 1/2 - 1.5 hp, having not done this with small pumps and having incomplete information on this pump as I got it for free I'd like a little help.

The motor says 4hp, the nameplate is still intact. The inside and outside of the pump has numbers on it that point to a hi flo model pump.


315-2500
https://www.amazon.com/Waterway-315-2500-Hi-Flo-Discharge-Volute/dp/B0038O8PES

E128519
Waterway Pump Parts 311-2140 3112140 Faceplate for Hi-Flo Series pumps, E128519

Do I need to just buy a impeller or do I need a diffuser and or water slinger? I also plan on changing the shaft seal.

 

[zea3]

I found some information here: How To Downsize a Pool Pump Impeller - INYOPools.com

You may need to replace the diffuser as well .

 

[kj5kb]

Not trying to derail thread...but is it worthwhile to try to downgrade a 4HP to 1.5HP? Seems a new 2 speed 1HP replacement motor would be the best way to go. 1HP should be plenty for that size pool.

 

[cfherrman]

Motor and pump are free, seal diffuser and impeller are $40 and that gives me a 220v 2 speed 1.5 hp pump.

Still haven't ordered anything yet, I don't have a big enough filter

 

[kj5kb]

Motor and pump are free, seal diffuser and impeller are $40 and that gives me a 220v 2 speed 1.5 hp pump.

Still haven't ordered anything yet, I don't have a big enough filter

But will you be paying for 1.5HP of electricity or closer to 4 HP worth, even tho it's 1.5 HP output...?,

 

[cfherrman]

Electric motors only draw what they need in output, the efficiency might be different as a 4 hp motor will be bigger than a 1.5 hp and have more rolling resistance.

For example, numbers pulled out if thin air
1.5 impeller with 1.5 motor, 10 amps drawn, 9.9 used for impeller, .1 lost due to efficiency.
1.5 impeller with 4 hp motor, 10.2 amps drawn, 9.9 used for impeller, .3 lost due to efficiency

Other possible concerns is cost or wiring a 220v motor, motor being junk or going bad soon. 220v is a very hair more efficient over 120 with all things being the same.

 

[kj5kb]

I guess we shall see...