How to choose a pump?

[river-wear]

I have a single speed pump that's about 4 years old. My husband says it's starting to leak, and even though I'm usually the one to maintain the pool I haven't looked at it yet. Assuming it's something that can't easily be repaired (or even if it can, I guess) - would it save enough electricity in a year to pay for a new two-speed pump?

We run it about 8 hours a day in the summer, 2 hours/day in winter and ramp up and down between the extremes (by manually adjusting the timer) as the water temp changes with the season. The load on the pool is low since we only use the pool about a dozen times per year. There are no water features.

Any suggestions on where I can find information on the Internet to help me make a good decision. I don't even know how to determine the right size/horsepower.

[river-wear]

I was reading about the Pentair Intelliflo that is supposed to reduce energy costs up to 90%. Is that complete overkill for a pool like mine, that doesn't have lots of bells & whistles? I replaced the timer with a simple dual mechanical timer for the pump & sweep last summer - will that have to be replaced again for even a dual-speed pump?

Any guidance appreciated. I'm clueless on this at the moment, but will keep googling for answers...

[CarlD]

I have a 2 speed pump and a mechanical timer. The speed is manually set at the pump. Simple.

You need to make sure your new pump's output at full speed doesn't exceed you cart filter's capacity, or it will damage your cartridges--to much pressure will tear the paper.

Don't be confused by the "Bigger Horsepower" thing. I suspect (and this is a W.A.G.) that with your pool, a full-rated 1.5 hp is the BIGGEST pump you should use, and only if it's 2 speed. You may be fine with a really high-quality full-rated 1 hp. If so, that's what you should get.

But I'll let the pump experts give you more detailed advice. In the meantime please list the model and size of your filter. They'll probably ask you how it's all plumbed as well.

[mas985]

river-wear,


If you have a single pump running the pool, spa and polaris, then you will probably need something closer to 2 HP. However, as Carl pointed out you do not want to exceed your filter rating.

If you can give us some more details, we might be able to help better. Things that influence pump size are:

Spa and # jets, are jets on their own pump or shared with pool?
Polaris with or without booster pump?
Pipe diameter/lengths?
Current filter size and PSI?
Current pump HP and service factor?

Poolplaza has one of the best tutorial sites out there for pumps:

http://poolplaza.com/pool-pump-sizing-2.shtml

[river-wear]

Thank you for the pointers.

My filter is a Pentair Clean & Clear Plus, CCP420. Filter area is 420 sf, flow rate 150 gpm. I found maintenance receipts from the previous owners; the filter was installed 9/04. I think the pressure gage usually reads about 10psi when it's running.

The pump I have is an A.O. Smith "conservationist" 1.5HP - or at least that's the motor. It was installed 2/05. At $249 (plus labor) I'm guessing they only replaced the motor. (????) Service factor says "1" on the side.

The spa does NOT have its own pump; it has four jets.
The pool sweep DOES have a booster pump.
Looks like the pipes are 2" ID. Which lengths do you need? The distance from the equipment to the farthest point is about 40-45 feet.

I'll check out that website now - thank you for that.

[mas985]

OK, since the filter is fairly large and can handle high flow rates, the spa will set the requirements for your pump. Are you happy with the jet action? Too hard, too soft, etc. If you are ok with it then you need to target a pump with the same braking HP of what you have which is 1.5 BHP (1.5 * 1.0).

Todays high efficiency pumps have pretty high service factors so you may only need a 1 HP (labeled) full rate pump to match what you currently have. For example, my 1 HP Northstar pump has a service factor of 1.85 which is 1.85 braking HP. This pump would be more than enough for your setup. One thing to do is to compare the pump head curves, if you have one for your current pump.

As Carl suggested, a 2 speed version would be the way to go so that you have high speed for the spa and low speed for general circulation. Sta-Rite, Pentair, Hayward all make fine high efficiency two speed pumps. The Pentair Intelliflow is another option for multiple speeds but you will pay for that feature.