HELP-Downsize filter pump motor?

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psal
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My Pool: 38 X 18 Oval. 3' @ shallowest, 6' @ deepest.
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Location: ca

HELP-Downsize filter pump motor?

Postby psal » Wed 26 Oct, 2011 10:01

Recently bought a house w/ a 18-20,000 gal in-ground salt-water pool. I have a pool guy who is helping me get started and he is suggesting that I replace the 2 HP motor on the filter pump with a 1HP (The spa has it's own pump). How much electricity will this save? Will I have to replace the impeller?
Any thoughts?
Thanks,


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mas985
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HELP-Downsize filter pump motor?

Postby mas985 » Wed 26 Oct, 2011 10:25

Yes, when downsizing a motor you will have to change the impeller and may have to change the diffusor as well.

In terms of savings, it depends on the pump but as an example, the Whisperflo 1 HP will use about 15% less energy than the 2 HP including changes in run time. You would save much more in energy costs if you also went with a two speed. A two speed on low wil cost about half of the high speed setting including changes in run time.
Mark
Hydraulics 101 ; Pump and Pool Spreadsheets ; Pump Ed 101
18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, Solar Panels, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater
psal
Pool Newbie
Pool Newbie
Posts: 4
Joined: Wed 26 Oct, 2011 09:07
My Pool: 38 X 18 Oval. 3' @ shallowest, 6' @ deepest.
Pebble-tec, salt
Location: ca

HELP-Downsize filter pump motor?

Postby psal » Wed 26 Oct, 2011 10:36

Thanks Mark....I mentioned a 2-speed motor to pool guy, but he said I would need to make changes to the controller (Jandy)...The pump is a Whisperflo WFE-8 Service factor 1.3. Do you believe this to be true?
Thanks for your help!
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mas985
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HELP-Downsize filter pump motor?

Postby mas985 » Wed 26 Oct, 2011 10:39

What is the Jandy controller model? Most controllers handle two speeds but I don't have a lot of experience with Jandy.
Mark
Hydraulics 101 ; Pump and Pool Spreadsheets ; Pump Ed 101
18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, Solar Panels, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater
psal
Pool Newbie
Pool Newbie
Posts: 4
Joined: Wed 26 Oct, 2011 09:07
My Pool: 38 X 18 Oval. 3' @ shallowest, 6' @ deepest.
Pebble-tec, salt
Location: ca

HELP-Downsize filter pump motor?

Postby psal » Wed 26 Oct, 2011 11:10

Thanks for taking the time to help.
The Jandy model is an Aqualink RS.
Would I want a 2HP 2-speed or would a 1HP 2-speed suffice?
psal
Pool Newbie
Pool Newbie
Posts: 4
Joined: Wed 26 Oct, 2011 09:07
My Pool: 38 X 18 Oval. 3' @ shallowest, 6' @ deepest.
Pebble-tec, salt
Location: ca

HELP-Downsize filter pump motor?

Postby psal » Wed 26 Oct, 2011 11:31

Forgot to add that pool guy says a 2-spped would be a waste since this pump motor does nothing but circulate and I have more than enough suction currently to handle the vacuum.
The spa has it's own pump as does the waterfall feature.
Agree?
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mas985
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Joined: Tue 08 Sep, 2009 10:40
Location: Pleasanton, CA, USA

HELP-Downsize filter pump motor?

Postby mas985 » Wed 26 Oct, 2011 18:16

psal wrote:Forgot to add that pool guy says a 2-spped would be a waste since this pump motor does nothing but circulate and I have more than enough suction currently to handle the vacuum.

I'm not sure what his point is but if he is saying that the vacuum may not work on low speed, that is true. Both vacuuming and skimming won't work as well on low as high but the energy savings are significant. What I do is run on high speed for a couple of hours a day for the vacuum and skimming and the rest of the time on low speed. High speed is also used when solar is engaged. So while you may not run on low speed all of the time, you will still save quite a bit when you do.

Also, you shouldn't need a 2 HP pump unless you are also running spa jets and/or a waterfall. If the pump is used for only circulation/cleaning then the smallest available pump would appropriate. I am currently using a 1/2 HP two speed for a 20k pool which works fine for even solar. So I wouldn't go higher than a 3/4 HP two speed.
Mark
Hydraulics 101 ; Pump and Pool Spreadsheets ; Pump Ed 101
18'x36' 20k gallon plaster/gunite pool, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge Filter, Solar Panels, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater
allclearpools
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HELP-Downsize filter pump motor?

Postby allclearpools » Mon 28 Nov, 2011 17:49

What is the size and type of filter you have? Any water features? Pool equipment elevated or below pool level? These all must be considered also. Goodluck finding a 1/2 hp 2 speed.

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