What size pump is adequate?

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ekh443

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Aug 31, 2015
10
Stevenson Ranch, CA
Hello,

I just purchased a home with a 18,500 gallon pool. The pump is a Hayward 2 HP pump single speed. I noticed that it costs me a lot of electricity to run this thing. I'm looking into switching it out to a variable speed pump. Do I need a 2HP pump for this size pool? Thank you for your help.

Eric
 
You can go with the smallest pump available as long as you are not trying to operate a spa or other high volume water feature.
 
Welcome to TFP!

Here is a good small VS pump. Pentair SuperFlo VS Pump 342001 | Pentair 342001

I have this pump, Pentair IntelliFlo Variable Speed Pump 011018 | Pentair 011018, it runs at 1100 rpm for filtering, skimming and making chlorine and only uses 150 watts. At 10.25c/kWh I can run it 24x7 for less than 12 bucks a month.

Give us some more details about your pool and we can probably give you some better advice. Here is more on adding your info to your signature, Pool School - Read This Before You Post
 
I would certainly replace it with something more economic to run, exactly what depends on a number of details, such as do you have an automation system, how a bout a heater? Then comes water features, and type of filter you are using...
 
Yes, that is why you need a 2 HP pump. Reducing the pump size would reduce the strength of the jets.

However, if energy consumption is of issue, you could convert the pump to a two speed and run on low speed when just filtering and circulating the pool. This will save about 75% in energy costs.
 
If I'm reading your signature right, you have a salt-water chlorine generator (AquaRite), correct??

If so, you need to be careful about downsizing or changing your pump size. While I fully support using energy efficient pumps and all the advice presented above, you need to make sure that if you change the single speed pump HP or, if you switch to a 2-speed pump, that you have enough flow to satisfy the SWG. All the major manufacturers have SWG's with flow switches to protect against the cell turning on if the pump is not running. We have seen people make a mistake in setting up a 2-speed pump only to find that the low speed of the pump is insufficient to run the SWG. So then they are left with a 2-speed pump that they constantly have to run on high speed to get chlorine generation. This is a reason why some will opt for a variable speed pump because it allows them to access a range of speeds to satisfy their various needs - low speed for skimming, middle speed for skimming and chlorine production and high speed for the spa and vacuuming.

So just be sure that whatever route you go, you make sure the flow requirements for your SWG are met properly.
 
The most popular VS pump around here seems to be the Pentair Intelliflo 011018. It's a 3hp pump so there is plenty of power for your spa. Has an onboard timer/controller that can be programmed to just the right speed/flow of any task. I have one an I just love it. I have separate speeds programmed. In the am it runs a couple hours at 2800rpm to clean, then switches to 1400 for the SWG to chlorinate for a while during the day, then drops to 1000 (just 100watts of power) for several more hours. If the solar heating system calls for heat, it speeds it up to compensate.

This pump would have plenty of power for the spa jets, can be dialed in to the most efficient speed to operate the SWG and can move lots of water with very low power use. They cost about $850 online. But if you want a full warranty you will need a receipt for "professional installation".
 
ekh443 said:
I understand. I guess the best option is for me to go with a VS 2HP pump. Any recommendations on which brand/model? Thank you all so much for your help!
Click to expand...
I just wanted to mention that you could just replace the motor of your current pump with a two speed motor and get most of the benefit of a VS pump at much lower up front cost and without any plumbing changes. However, if it is more important to save more down the road, then the VS is probably the better choice.
 

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One big concern with a two speed pump is you have to be very sure that the flow on the lowest speed is sufficient to activate the flow switch on the SWG. If not you will be running the pump on high to chlorinate the pool, negating any potential savings.
 
I recommend that you go with the Pentair 3HP Intelliflo VS pump. Fear not the 3 HP rating as in my mind it matters little with a VS pump. You will most likely be running it at 1500 RPM, or less, most of the time and just guessing that is probably less than a 1/4 HP. It uses about 300 to 400 watts of power at that speed. When you use your spa you can ramp it up to whatever speed works for you.

Jim R.
 
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chiefwej said:
One big concern with a two speed pump is you have to be very sure that the flow on the lowest speed is sufficient to activate the flow switch on the SWG. If not you will be running the pump on high to chlorinate the pool, negating any potential savings.
Click to expand...
My SWG has no issues on low speed of my 1/2 HP pump so I doubt there would be any issue with low speed of a 2 HP pump.
 
Jimrahbe said:
I recommend that you go with the Pentair 3HP Intelliflo VS pump. Fear not the 3 HP rating as in my mind it matters little with a VS pump. You will most likely be running it at 1500 RPM, or less, most of the time and just guessing that is probably less than a 1/4 HP. It uses about 300 to 400 watts of power at that speed. When you use your spa you can ramp it up to whatever speed works for you.

Jim R.
Click to expand...

Actually the draw is less than that.
The great thing about a VS pump is you can dial in the precise speed that saves the most (and is quietest) for any particular function. 1200rpm (which will work with most SWG) takes only 150 watts on my system. If I have to go all the way to 1400rpm it still uses only 200 watts. My old single speed 2hp pump was using 2,800 watts whenever it was running, while the new pump never exceeds 1600 watts (3100rpm) and spends most of its time running at 100 watts (1,000 rpm)
The only time you would ever have any significant power usage with a VS would be operating the spa or cleaning.
 
If you want a cheaper option look at the smaller Hayward VS pumps like the MaxFlo VS (not to be confused with the non VS version of the MaxFlo). They are smaller and much cheaper than the Intelliflo, but have the disadvantage of no external controller interface so you have to use the build in control panel to change run speed. There is also a built in basic run timer so no need for an external timer.
 
Isaac-1 said:
If you want a cheaper option look at the smaller Hayward VS pumps like the MaxFlo VS (not to be confused with the non VS version of the MaxFlo). They are smaller and much cheaper than the Intelliflo, but have the disadvantage of no external controller interface so you have to use the build in control panel to change run speed. There is also a built in basic run timer so no need for an external timer.
Click to expand...
With a spa, I think he will appreciate the additional power available from the larger pump.
 
I agree. Both the Superflo and Maxflo VS pumps are lower head pumps and are not really appropriate for spa jets unless you have just 4 or less.
 
chiefwej said:
I have separate speeds programmed. In the am it runs a couple hours at 2800rpm to clean, then switches to 1400 for the SWG to chlorinate for a while during the day, then drops to 1000 (just 100watts of power) for several more hours.
Click to expand...

As I start the process of experimenting with different rpm and run timse settings, I was wondering how/why you came to set the rpm at 1400 rpm to generate chlorine off the T-15 SWG. Was that the minimum rpm threshold for the T-15 to generate chlorine? That is, will the T-15 allow for a lower speed setting before the kill switch is activated?
 
Jaimslaw said:
As I start the process of experimenting with different rpm and run timse settings, I was wondering how/why you came to set the rpm at 1400 rpm to generate chlorine off the T-15 SWG. Was that the minimum rpm threshold for the T-15 to generate chlorine? That is, will the T-15 allow for a lower speed setting before the kill switch is activated?
Click to expand...

Minimum rpm will vary, depending upon your plumbing, type and size of filter, etc. In my system the SWG flow switch was working fine at 1200rpm. I set the pump speed at 1400 just to provide an extra margin for when the filter gets dirty, and reduces the flow. There are others who are running an AquaRite T-15 with an Intelliflo pump running as low as 1000rpm. So your experience may vary.
 

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