1.5" plumbing for ~ 21k gal pool...how to optimize the plumbing at pad

[Natezo]

Hi All!

First post for me...I'm preparing to setup and lay out my pad for my new 18x36 mountain loch pool build. I already have roughed the plumbing to the pad, so I'm stuck with the 1.5" that I installed. I read later in the project about 2" and 2.5" being better, but since that's no longer an option, I'm trying to optimize my circulation and efficiency with what I can still change. I've attached some images to help establish some of details, but if more is needed I can add as needed.

Also, I live in CT so I'm looking at probably an average 5 months of operation per year...I have no plans for a pool heater, so it's just the pump and filter at this time.

Oh, and the pump and filter will be on a pad roughly 18" below the top of the water line of the pool...my lot is hillside, so my pad is on the back hill and below the waterline.

 

[ajw22]

Welcome to TFP.

You are not going to see any operational difference between 1.5 or 2” lines on your equipment pad. If you want to feel better plumb with 2”.

If you wanted efficiency get a VS pump.

 

[Yev]

You are not going to see any operational difference between 1.5 or 2” lines on your equipment pad. If you want to feel better plumb with 2”.

Really? I woudl guess if you used 2" pipe at the pad, as 2' lines can handle 1.8x the volume, you would have a lot less stress on the system. But more importantly, I would have assume that in you took 2 systems, plumbed one pad with 1.5' and the other with 2", both with 1.5' to the pool, that you would end up with more flow on the 2" stlye. Is that not true?

 

[ajw22]

You have a single speed pump. You have pretty much a fixed flow rate. Theoretically there is a small difference. Practically you will not see an operational difference.

There is no stress on the system. Your pump has plenty of HP to move the water.

Your system is limited by the 1.5" pipes in the ground. Larger pipes in the pad make little difference.

 

[mas985]

Really? I woudl guess if you used 2" pipe at the pad, as 2' lines can handle 1.8x the volume, you would have a lot less stress on the system. But more importantly, I would have assume that in you took 2 systems, plumbed one pad with 1.5' and the other with 2", both with 1.5' to the pool, that you would end up with more flow on the 2" stlye. Is that not true?

Theoretically, that is true but it comes at a cost of higher energy use too. But as Allen points out, it is a minor difference in flow rate. Not usually worth a redo.

 

[Yev]

Theoretically, that is true but it comes at a cost of higher energy use too.

Are you saying that 2" on the pad and 1.5" to the returns uses more energy than 1.5" everywhere?

 

[jimmythegreek]

If the pump amd filter are 2" fittings then use all 2" at the pad. Make a manifold and gonim amd out from there. I would install 2 way valves on each line. You will need at least valving to shut down each side if below pool for when you have to clean basket or filter.

 

[mas985]

Are you saying that 2" on the pad and 1.5" to the returns uses more energy than 1.5" everywhere?

Yes. More head loss in plumbing reduces flow rates which reduces energy use in a centrifugal pump.

However, the flow rate reduces faster than energy use so pump efficiency also goes down.