Swimming pool pump sizing question.


I need to replace my pool pump as the bearing are gone and I am leary of previous cavitation trouble. I have been to three different pool stores and have been given three different recommendations. Now I want the real answer, not just what they are trying to sell me.
Specs:
20,000 gal pool Pool/Spa combo with 4 spa jets 2" PVC supply lines 2" PVC return lines Pump - currently a Pentair Whisperflo 1HP Full-rated 115/208-230 volt (original equip from 1986) Filter - Jandy CL460 Cartridge Heater - Raypak RP2100 Natural Gas Cleaner - Suction side Kreepy Krauler type Equipment is located about 40 feet from the skimmer Need to have a pump that is as quiet as possible as it is located right under a window of our house.
Advice so far:
1. Replace only pump MOTOR and seal with same exact single speed 1 HP Whisperflo motor. (Was told least expensive and all that needed to be done)
2. Replace entire pump with single speed 3/4 HP Full-rated Pentair Whisperflo. (Was told the larger pump size causes cavitation and is louder, and that 3/4 is plenty strong enough for spa jets)
3. Replace entire pump with 1.5 HP Full-rated Pentair Whisperflo. (Was told needed larger pump to match large filter size and decrease circulation time)
4. Replace entire pump with 1 HP dual speed Pentair Whisperflo. (Was told it is the quietest ,most energy efficient, but more likely to malfunction early and much more expensive)
Questions:
1. Is filter oversized? It is brand new, put in by the pool company that replastered. 2. Which option above is best for this pool? Or other option even better?
Thanks!
Wes
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How does one pump do both the pool and the spa, with different temps?
Nick
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I think this is pretty standard plumbing.
A valve controls where the water is coming from pool or spa, and another valve controls pool or spa return. There is an overflow form the spa to pool if needed.
I have to isolate the spa circulation and "bring the spa up to temp" when I want to use it.
Wes
snipped-for-privacy@ece.villanova.edu wrote:

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Wes writes:

What does Jandy say?
Oversized? Undersized is what you worry about.

Go with the lower HP, 1 or 3/4. Smaller pumps are much more efficient. Cheaper to run them longer for the same volume pumped than a larger motor in shorter time. Better for your pool sanitation as you're circulating and skimming longer during the day for the same money.
That said, if your existing motor just has bad bearings, bearings are cheap, maybe $10 for a set. They don't like you to know that at the pool store, of course, and will deny that you can fix them. But unless your motor is literally burned out, or corroded badly, you can just disassemble the pump and motor and replace the bearings. Look for a bearings distributor locally, or as a second choice an electric motor repair shop. Or just measure the old bearings and order them out of http://www.mscdirect.com /.
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I bought them at the pool equipment store. Bearings and seal.
Bob
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your climate and trees and bather load are important missing pieces of your puzzle. in buffalo ny: our 12,000 gallon above ground uses a 2 speed pump so you can vacuum or open your season with plenty of water flow and turnover of the chlorine shock level. depending on how you skim the pool's surface a pump that's too small won't suck enough to skim. we use the low speed more in cooler weather with less bather load. the high speed is good thru summer with high bather load and to catch the falling spring seeds and early autumn leaves from the trees before they sink to the bottom. swimming season begins in may is over on september labor day and we cover the pool before the leaves start falling. here's a good site: http://www.haywardnet.com/pdfs/Pump_filter_sizing.pdf and: http://www.haywardnet.com/inground/products / general info: http://en.wikipedia.org/wiki/Swimming_pool energy saving stuff that doesn't work for us at: http://www.eere.energy.gov/consumer/your_home/water_heating/index.cfm/mytopic290
Wes wrote:

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