Over Sized Pump? New Pool Guy

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mobileguy

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Mar 22, 2010
23
Purchased a house in Nov that came with a 36ft by 18ft 33,000 gallon pool. After many long hours larking the forum I believe my pump is WAY over sized.

Pump: Jandy Stealth
Model: SHPF3.0
3hp

I have 1 1/2 pipes going underground to the pump from the looks of it.

Filter: Hayward Pro Series
Model: S220T

After researching I was thinking of taking off the Pump and replacing it with a 1HP or 1/2 HP motor. What do you think?

Also, could some describe these pipes? Returns?
photo.jpg
 
mobileguy said:
After researching I was thinking of taking off the Pump and replacing it with a 1HP or 1/2 HP motor. What do you think?
Click to expand...
Welcome to the forum :-D

Congratulations on your new house and pool! Though hardly an expert in pump sizing (both a science and art, evidently) I can assist by suggesting that you post a little more information about your current system.

Are you wanting to replace the pump just for energy efficiency or some other reason?

How many hours a day is the pump normally on for circulation/filtering?

What is the distance between equipment pad and pool?

Also, it would helpful to know...
The other components of your pool that impact flow rate, such as a spa, water features, automated pool cleaners, heaters, SWG, solar, number of returns, skimmers etc.

If you know or have estimated the current GPM, include this and the PSI at the filter.
 
I'm thinking if the pump is oversized it can lead to filter and plumping failure?

I have yet to run it, but the timer is set on I believe 8 hours.

10-15 feet.

None listed above. No additional components.
 
Yeah, I'm no expert either but I'd say unless its a variable speed it's probably oversized which can lead to channelling and other filtration issues, not to mention a high elec bill.
If you are swapping it out consider a 2 speed pump which can yield great savings on your elec bill.
 
A 3 HP pump is way too large for a simple pool without a spa or water features, even if it is 33,000 gallons. I doubt that a large pump could cause any damage to the plumbing, but it could certainly put a strain on all but the largest filters and significantly lower their filtering ability.

You shouldn't replace just the motor on your existing pump with a different size motor, without also replacing the impeller. Replacing the entire pump is fine.

The S220T is designed for a 52 GPM flow rate, while your current pump should be putting out over 100 GPM. You only need 46 GPM to get two turnovers a day, or 69 GPM to get three turnovers, so a much smaller pump will be fine. A smaller pump, especially a two speed pump or a variable speed pump, will also save you quite a bit on electricity.
 
And a 3 HP pump will cavitate because it's starved. A 1.5" pipe cannot supply a sufficient volume water due to the head loss. The faster water travels through plumbing, the more friction there is and it goes up very, very quickly as the speed increases.

If this pool was plumbed with flex pipe, the suction lines could collapse under ground.

Skimmers may suck air if the water isn't kept higher than normal, and even then, they can be overwhelmed.

I doubt there is a VGB compliant drain cover. The suction there is very strong in this case and poses a serious safety concern.

As we have said, reducing the size of that pump is VERY important and not just because of the energy it wastes, but more because of the safety factors and potential for additional and expensive repairs it would cause.

Scott
 

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Also, I only want to spend $200-$350 on a new pump. Which make and model should I get for best energy efficiency?

I would like to stick to 3/4 HP because I believe i could run it 8-10 hours a day for low energy costs compared to 1 HP.
 
mobileguy said:
Also, could some describe these pipes? Returns?
Click to expand...
Your picture is a little close to tell for sure but the three that are disconnected appear to be returns. Do you have three returns in the pool? As for figuring out which is which you can turn them off one at a time once you get the pump running and figure out where they are.
 
Hey Mobileguy,

I've been lurking for a couple of weeks and I have a similar situation as you do. Just bought a house. I have a 2hp pump with a pool that is smaller than yours with an inground spa. The water fall has a 1.5 hp pump. I'm very curious as to what you do and your results.
 
You really can't tell the efficiency of a pump by just looking at the motor amp rating. The GPM/Watt-hr is better metric to use and the CEC publishes GPM/Watt-hr ratings for nearly every pump on the market (see pump energy comparison link in my sig). The Whisperflo is one of the more efficient pumps on the market and is a more efficient pump than the Superflo series.
 

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