Need help selecting new pump

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JPE

Need help selecting new pump

Postby JPE » Tue 05 May, 2009 09:57

My existing pump is EXTREMELY noisy and I want to replace it with a quieter pump and, preferably, a pump that is more efficient. Obviously, whichever pump I choose needs to work with my existing equipment.

I've been to several sites to try and determine what I need, but it is very confusing. I've contacted both Hayward and Pentair with the following specifications, but they won't recommend a specific pump and just tell me to call their local reseller. I intend to purchase it locally and have the local retailer install it, but I'd feel better if I was getting expert advice from someone who understands the relationship between the pump and my specific pool equipment, rather than taking advice from an untrained sales clerk who seems intent on selling me the “world’s most popular” pool pump.

Can anyone here help?

Here is my specific pool information:

Gallons: 37,000 +/-
Shape: modified Grecian with spa at one end
The spa has 8 jets

NOTE: There is a Paramount 6-zone floor cleaning/circulation system with water valve/timer. Most zones utilize only a single pop-up return head; a few use 2 heads; one of the zones is for 2 ‘normal’ (non-Paramount) wall return outlets


Current equipment:
Jandy Aqualink RS controller with spa-side remote
Prozone Ozone generator – model PZ2-2 with forced injection pump
Water/Pool Pump: Magnatek Centurian Switchless
Cat # B808 / part # 8-165123-05
208-230 volt
3450 RPM
Amps = “SF 10.4-9.6”
SF = 1.20
HP = 2.0
Incoming pipe fitting is 2½ inch outer pipe diameter
Exiting pipe fitting is 2 inch outer pipe diameter
Height above water line = approx. 1 to 2 feet
There is a check valve before input
The return (toward pool) line is 2¼ inch outside diameter
The return (toward spa) line is 2¾ inch outside diameter
The skimmer suction line (from pool) is 2¼ inch outside diameter
The floor/drain canister suction line (from pool) is 2¾ inch outside diameter
The spa suction line (from spa) is 3¼ inch outside diameter
Estimated suction pipe length:
Spa drains (2) to pump inlet = approx. 100 feet (incl. vertical)
Main drains (2) to pump inlet = approx. 65 feet (incl. vertical)
Skimmers (2) to pump inlet = approx. 50 feet and approx. 85 feet
Estimated return pipe length:
To spa (8 jets) = approx. 100 feet
To Paramount water valve = approx. 70 feet
To pool outlets (from water valve): varies by zone: add 20-50 feet – depending upon zone

Filter: WET Institute model M330 AP-2 cartridge filter
Filter area = 330 square feet (3 cartridges)
Maximum working pressure = 50 psi
“Normal” pressure reading (clean) is 16-20 psi (pool mode) / 10-14 psi (spa mode)

Heater: Laars LT gas heater – 400,000 BTU

Air Blower: unknown make

Thanks for your help!


Me...
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 302
Joined: Thu 26 Feb, 2009 11:11

Need help selecting new pump

Postby Me... » Tue 05 May, 2009 12:03

The 2hp looks like a good selection for that pool, I would have been in that range looking for around 150gpm. Your jets would be wanting a nice average of 20gpm each. In-floor cleaning systems want lots of pressure and your Ozone system will want some nice pressure drop over the venturi to be able to draw nicely.

The problem I see is that 150 gpm requires 3" ID plumbing to be proper and efficient. Anywhere you can see ALL the water trying to pass through anything less it will create a restriction which WILL draw extra energy and possibly add extra noise. Hopefully there are not many lines that handle the total flow and are less than 3" ID. If there are, hopefully they are short runs of pipe.

In any event it looks like you need a 2hp pump and I would pick a Pentair Whisperflow 3hp model number WFE-8.
JPE

Need help selecting new pump

Postby JPE » Tue 05 May, 2009 12:34

Me... wrote: your Ozone system will want some nice pressure drop over the venturi to be able to draw nicely.

In any event it looks like you need a 2hp pump and I would pick a Pentair Whisperflow 3hp model number WFE-8.


Thanks for your reply!

The Prozone PZ2-2 ozone generator has a supplemental air compressor pump as there is apparently too much back pressure resistance from the PCC-2000 floor system to work without it.

As for the Whsiperflo recommendation, I'm confused because you say I need a 2HP pump, but you've recommended a 3HP model. Am I missing something?

Also, I've provided the pipe diameters and approximate lengths in my original description. I'm not entirely clear how they impact the recommendation, which is why I included that information.

By the way, there is also what they call a "Hartford Loop" in the plumbing line. I don't know if that has a bearing on anything here.

Thanks,
John
Me...
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 302
Joined: Thu 26 Feb, 2009 11:11

Need help selecting new pump

Postby Me... » Tue 05 May, 2009 20:13

My bad, WFE-8 actually is a 2hp pump.

Ok, sounds like you have a pressure Ozone system then which explains the lack of a booster pump description. The Hartford is probably in the Ozone injection line and is there to help prevent any back flow from flooding the generator. Hopefully there is also a check valve.

The spa suction line is the only one that seems big enough to properly handle 150gpm. You may have scads of 3" plumbing underground and only a very little bit of smaller plumbing visible, I simply don't know. Fact is and efficient system will use 3" plumbing. That by the way is the inside diameter. 2" is good to about 80-90 gpm, 2.5" maybe 125gpm and 3" up to about 200. If you exceed those flow rates you start to increase backpressure and velocity which in turn can create noise, erosion and of course excess work for the pump which costs money.

Since your Ozone system can self feed you may want to consider this. The only thing then that requires high flow/pressure is the in floor cleaning system and chances are it doesn't need to run more than a couple hours a day. Have a 2hp-2speed pump installed and run it on low speed unless you need high speed. That pump will pay for itself inside of 2 years with saved electrical costs I bet. Also less noise. It could be installed on a timer so it only came on to run the cleaning system during a 2-3 hour period in the mid afternoon or so.

Now that said, check with your Ozone guy to make sure the reduced flow will be ok. Some guys put way too powerful a system on. I would bet that pump on low speed will do about 40-50gpm on low which would run the heater. That flow should be able to handle about a 3gr.hr. generator but best to check. If the Ozone is running through your in floor cleaning system the increased Ozone concentration could speed up the degradation of your cleaning heads etc.

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