PVC size

[orthofish]

Is there any advantage/disadvantage to haveing 2" PVC on the suction side and 1.5" on the return side??

 

[mas985]

Pumps prefer lower head loss on the suction side vs the return side so normally a large pipe size is used on the suction side. However, I would go with at least 2" on both suction and return.

If you have only 1 suction line, then I would increase that to 2.5". More than one suction line, you can get away with 2" line unless it is a high flow application (e.g. spa, waterfall, etc). For that you might need 2.5" or even 3".

A single 2" return line is usually enough but larger there would not hurt as well. Again, larger for higher flow applications.

Given that larger pipe is not that much more expensive than smaller pipe relative to the total cost of the pool, it is worth it to upsize the pipe.

 

[duraleigh]

Hi, Mark,

I have (2) 2-inch suction lines coming from the pool. It makes sense to me to bring them together before entering the pump with a 2.5" pipe. However, the pump inlet only accepts a 2" fitting. Will I gain anything significant if I run the 2.5" into it? The 2.5" run would be only about 3-4 feet.

 

[orthofish]

I will have a skimmer and main drain, both with their own line. 2 returns and 2-4 deck jets.No other water features. Could possibly do solar panels down the road.

One of the two PB I'm talking to said they used a flexable line from the main drain to out of the ground, and also used about a foot or so of this flexable line from the back of the skimmer and returns. They said it would allow for any settling of the fiberglass pool since just a small shift,1/8 of and inch, could cause a union to leak. Does this sould right?? They gave me a piece of the pipe. It appears to be quite strong but does have a bit a flex to it.

 

[mas985]

I have (2) 2-inch suction lines coming from the pool. It makes sense to me to bring them together before entering the pump with a 2.5" pipe. However, the pump inlet only accepts a 2" fitting. Will I gain anything significant if I run the 2.5" into it? The 2.5" run would be only about 3-4 feet.

3' of 2" pipe has about the same head loss as 9' of 2.5" pipe. In a typical plumbing system, there are several hundred feet of equivalent pipe length so the % change isn't likely to be much.

If you need to replace that pipe anyway I would say go ahead but if you just want to do it to lower head loss then I would say it probably isn't worth the trouble.

 

[mas985]

I will have a skimmer and main drain, both with their own line. 2 returns and 2-4 deck jets.No other water features. Could possibly do solar panels down the road.

One of the two PB I'm talking to said they used a flexable line from the main drain to out of the ground, and also used about a foot or so of this flexable line from the back of the skimmer and returns. They said it would allow for any settling of the fiberglass pool since just a small shift,1/8 of and inch, could cause a union to leak. Does this sould right?? They gave me a piece of the pipe. It appears to be quite strong but does have a bit a flex to it.

So with two lines on the suction, 2" is probably ok and you can match that with a single 2" on the return and the pump should be happy.

As for the flex pipe, it is useful where you might expect some significant movement. I have heard that they are making it much better these days and that some pools are being installed with all flex.

 

[orthofish]

Thank you Mark.