Dual speed vs. variable speed motor?

caliking

Well-known member
May 11, 2012
60
Houston, TX
Greetings all.

Setup=
Pentair Challenger pump
Century Electric B855 2HP (THP=2.2) single speed motor
18K inground pool (5 jets, 2 skimmers)
Water feature and Polaris cleaner each have their own pump.

The motor has always been rather loud, and recently became even louder. Plus, its an energy hog. I want to change to a dual speed or variable speed motor, and was hoping to tap the collective knowledge here for guidance.

I've been considering the following:
1. V-green 2.7HP 48Y VS This is the most expensive of the ones I'm looking at, but likely the most quiet (and energy efficient) motor. Will I need a new frame/mount, since its 48Y?

2. Century B2984 2HP 56Y Dual Speed Full Rate Likely won't be as quiet as the VS above, but will probably be a happy middle ground re: noise, price, and energy efficiency. I would buy a hi/lo switch, separately.

3. Century B2983 1.5HP SF1.47 56Y Dual Speed Full Rate From what I understand, THP is what matters. So, since this motor's THP is equal to my current motor, it should work?

4. If I go for a 1HP motor, I will probably need a new impeller. New diffuser too? Would I have to change the front housing of the pump as well, or simply swap out the impeller?

I'm not keen on changing out the whole pump because of the cost, and the plumbing. I have a union at one end, so that side would be easy, but the other end would be more involved.

The difference in cost between the V-green and the dual speed motors is quite a bit, which is why I'm leaning towards a dual speed motor.

Please feel free to suggest other options, or correct any of my misconceptions :)

Thanks!
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
32,631
Laughlin, NV
If those tablets are in a chlorinator device (this is where a signature filled out really helps) they take high flow rates to erode the tablets sufficiently to add the FC you need. Of course that comes with CYA. So you will not get much savings. A VS motor is probably best so you can run at higher rpm and still get a little savings.
I suggest you contact InyoPools and they can suggest what motor would work best for you.
 
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red-beard

Gold Supporter
May 27, 2019
518
Houston, TX
I suggest you go for Variable Speed, but go for the smaller pump. The 2.7 hp is overkill for 20,000. Get one of the 1.65 or 1.85 hp (maximum) VS pumps.

I have a 1.85 hp Hayward VS Tristar. I run it at 1050 RPM (40 GPM) most of the day, 61 Watts. That 2 hp monster is consuming 2,400 Watts. (10 Amps x 240 VAC). Even at 100 GPM, my pump runs about 870 Watts. I run 24/7 and consume about 4kWh per day. If you only run 8 hours per day, you are consuming 19 kWh. At $0.10 per kWh, that is about $700 per year.

I "thought" I had a 1/2 hp primary. Turns out my pool company replaced it with a 1 hp when it failed and they did not tell me. I ran 14 hours per day and spent about $800-900/yr on primary pool circulation.
 
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Darin

Well-known member
May 29, 2015
51
Muscatine/IA
One other thing. Since it appears that you have a replacemnt motor verify what pump you have. You may have a little bit of the Challenger sticker left on the other side of the pump. That is where mine is located. You may be able to get by with less hp if the motor was oversized when it was replaced. Good luck, and it is very quiet with a VS.
 
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JamesW

TFP Expert
Mar 2, 2011
20,402
For as much money as you will spend on a motor, I would not put it on such an old pump.

I would go with a new pump.

Check with Pentair and your local utility for applicable rebates.
 

caliking

Well-known member
May 11, 2012
60
Houston, TX
If those tablets are in a chlorinator device (this is where a signature filled out really helps) they take high flow rates to erode the tablets sufficiently to add the FC you need. Of course that comes with CYA. So you will not get much savings. A VS motor is probably best so you can run at higher rpm and still get a little savings.
I suggest you contact InyoPools and they can suggest what motor would work best for you.
The chlorine tabs go in a floating dispenser.

InyoPools suggested the V-green 2.7HP motor, but I hadn't thought of a dual speed motor when I contacted them initially. I'll get in touch with them, and see what they have to say.

Thanks.
 

caliking

Well-known member
May 11, 2012
60
Houston, TX
I suggest you go for Variable Speed, but go for the smaller pump. The 2.7 hp is overkill for 20,000. Get one of the 1.65 or 1.85 hp (maximum) VS pumps.

I have a 1.85 hp Hayward VS Tristar. I run it at 1050 RPM (40 GPM) most of the day, 61 Watts. That 2 hp monster is consuming 2,400 Watts. (10 Amps x 240 VAC). Even at 100 GPM, my pump runs about 870 Watts. I run 24/7 and consume about 4kWh per day. If you only run 8 hours per day, you are consuming 19 kWh. At $0.10 per kWh, that is about $700 per year.

I "thought" I had a 1/2 hp primary. Turns out my pool company replaced it with a 1 hp when it failed and they did not tell me. I ran 14 hours per day and spent about $800-900/yr on primary pool circulation.
I was starting to realize that the 2HP is way more than I need.

If I get the V-green 165, would I need to change the impeller? Diffuser? Front housing?
 

caliking

Well-known member
May 11, 2012
60
Houston, TX
One other thing. Since it appears that you have a replacemnt motor verify what pump you have. You may have a little bit of the Challenger sticker left on the other side of the pump. That is where mine is located. You may be able to get by with less hp if the motor was oversized when it was replaced. Good luck, and it is very quiet with a VS.
Here's what the pump sticker says:
1600206751874.png
 
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red-beard

Gold Supporter
May 27, 2019
518
Houston, TX
I believe if you stick with Pentair, it should mount right up to the plumbing. Check the manufacturer specs and dimensions. I replaced my Hayward Tristar 1 hp with the Tristar VS and it fit perfectly.
 
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caliking

Well-known member
May 11, 2012
60
Houston, TX
Thanks for the helpful advice, everyone.

Seems like the path of least resistance would be the V-green 2.7HP. I'll do some research and find out what changing to a 1.65HP VS motor would entail, but I'll likely pass if it looks like it will take more than a few beers to make the change.
 
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Darin

Well-known member
May 29, 2015
51
Muscatine/IA
caliking, your impeller on your pump is sized for a 2 hp motor. You probably do not want to swap out impellers unless you get a great deal on a used 1.5 hp one. Do not used an undersized hp motor on your pump. It does not matter if it is a single speed, dual speed, or a VS do not undersize the (thp) motor.
 

caliking

Well-known member
May 11, 2012
60
Houston, TX
caliking, your impeller on your pump is sized for a 2 hp motor. You probably do not want to swap out impellers unless you get a great deal on a used 1.5 hp one. Do not used an undersized hp motor on your pump. It does not matter if it is a single speed, dual speed, or a VS do not undersize the (thp) motor.
It will not "hurt" to have the 2.7. I have a buddy with a 12K pool with a 2.7. Before he changed it, he had a 3 hp pump!
Thanks for the clarification. That's the info I needed.

I don't think I will save much by trying to install a lower HP motor, because that would entail changing out the pump too. Looks like I'll be getting the V-green 2.7, unless anyone thinks there is a better VS motor to buy.

Thanks again!
 

red-beard

Gold Supporter
May 27, 2019
518
Houston, TX
That is a $200 savings over a Max Flow VS including the pump.

Wow! If I had a 1.5 hp Hayward laying around, the $399 for a VS motor for the pump would be great.