How to choose a pump?

[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.