Pump choice / pipe sizing into and out of pump housing

[syntax53]

I am looking to redo all of my aging equipment this season (pump, multi-port, filter, valves) as one valve cracked during closing and I had numerous problems with the pump housing, multiport, and filter last season. Currently I have a 1.5HP pump with 1.5-inch plumbing, a 37-sqft DE filter, and a ~30k gallon in-ground pool. 2 skimmers+floor drain, 2 returns + old vac port using as a 3rd return.

I had the local pool shop give me an estimate just to see what they would say and recommend. They recommended a 48-sqft filter, lowering the power on my pump to 1HP, and upping the plumbing to 2" (keeping the 1.5" lines in-tact that are under the deck-- multiple 1.5" lines into valves that feed into 2" piping... made perfect sense to me). However, since their price is higher than I would like it to be and I'm perfectly fine doing this stuff myself, I started piecing together my parts. And where I'm stuck on is the pump.

The pump I'm looking at right now is this 1.5HP hayward: https://www.amazon.com/Hayward-SP2610X15-1-5-HP-Max-Rated-Single-Speed/dp/B00198CW7G ... but it doesn't say the size of the pipe intake and discharge. Comments seem to suggest it's 1.5-inch. I can't find anywhere on this site or the internet to confirm. Plenty of people say, "just use an adapter" when questioning if it will work with 2" piping. But if I adapt down, then doesn't that defeat the whole purpose of going to 2" piping?

In regards to 1.5HP vs 1HP pump... My current 1.5HP pump takes awhile to prime as the the feet to head is up there (9.5' deep end + 20-30feet from pool to equipment) and I've always felt like the suction on the skimmers was a little lacking so I'm concerned about dropping down to 1HP. But if I do up the piping all the way through, then maybe that balances it out? Thoughts?

Looking at the Hayward DE4820 (which is 2" piping) DE filter.

 

[mas985]

A more efficient pump would be the SuperPump SP2607X102S.

Plenty of people say, "just use an adapter" when questioning if it will work with 2" piping. But if I adapt down, then doesn't that defeat the whole purpose of going to 2" piping?

No it doesn't defeat the purpose. It will still work fine.

n regards to 1.5HP vs 1HP pump... My current 1.5HP pump takes awhile to prime as the the feet to head is up there (9.5' deep end + 20-30feet from pool to equipment) and I've always felt like the suction on the skimmers was a little lacking so I'm concerned about dropping down to 1HP. But if I do up the piping all the way through, then maybe that balances it out? Thoughts?

9 times out of 10, priming issues are due to air leaks and has nothing to do with the pump or plumbing (other than the leak).

Does the pump need to prime every time it turns on? If so, that is an air leak because it should never loose prime unless you take off the pump lid.

 

[syntax53]

I understand it will "work," but if you have a 1" pipe in the middle of a 2" pipe, your flow is going to be restricted to 1", no? And therefor, defeat the purpose of upping the plumbing.

No, it doesn't lose prime.

 

[mas985]

I understand it will "work," but if you have a 1" pipe in the middle of a 2" pipe, your flow is going to be restricted to 1", no?

No. The smaller pipe has a little more head loss per foot of length but it doesn't limit flow rate in anyway. A bushing has very little head loss so the difference in flow rate is imperceptible.