Replumbing a small pool

[Kaa]

I have a small pool which is built into a deck and is kinda half-inground. It's rectangular, has hard walls of galvanized steel, and partially in the ground and partially above ground. The size is 18' x 8' and that makes it about 4500 gallons.

I'm re-piping it and going to use 1.5" flex PVC pipe which will all be above ground (but below the deck). I don't see any reason to go to 2", is there? The old pump is 1.5HP and I'll probably get a variable flow pump of the same HP, though it seems too much for such a small pool. I'll also put in a salt water generator.

By the way, choosing between Hayward and Pentair, Pentair does minimal warranty of DIY work (60 days, I think) and for that reason I was inclined towards Hayward. But I was also told that recently the quality of Hayward went way down and that makes me a bit worried about that. Any comments on that.

I'm attaching a couple of sketches of what I plan to do (UBV is union ball valve, SWG is salt water generator). Am I doing anything wrong?

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[zea3]

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You get a little less head loss with 2" pipe vs 1.5" pipe, but 1.5" pipe will work just fine. I would go with the smaller pump, even a two speed 1 hp pump would be plenty for your pool. If you are not running a bunch of different features you really don't need to pay extra for the multiple speed settings. With a 2 speed motor you filter on low and vacuum on high. As far as quality goes, in my 10 years of pool ownership I have replaced my Pentair Dynamo with the same pump about 3 times. Twice the motor casing rusted through on bottom, even though it wasn't touching the ground. The other time was an issue with the bearings. The Dynamo is their budget above ground pool pump. That alone would not steer me away from Pentair products, but I am tired of this particular model of pump!

As far as Hayward equipment goes, I have a Hayward sand filter and couldn't be happier with it. We get a few Hayward haters who say their pumps are garbage but I would say the majority are satisfied with their performance. Any major brand is going to work well, as they are pretty much all driven by A.O. Smith motors. Pentair, Hayward, and Jandy, are going to be good pumps. Check around for the best deal and warranty on a diy installation.

 

[azide999]

Aside from the great advice provided above, I would suggest using PVC-40 for the lines and only use flex PVC in one part of the line for the skimmer and each of the two returns. The cost would be much reduced, but also if you are worried about the plumbing lining up correctly, one piece of flex would be sufficient in each line. I did this so that at least one part of each line would be flexible.

On pumps, a 1.5 hp is quite large for that size of pool, and although there are minimal cost differences between 0.75, 1 and 1.5 hp pumps, the monthly electricity cost difference is substantial - perhaps $75:$100:$150 if run all the time (it actually comes out to that with my electricity rates, which are low). I wonder if a 0.75 hp 2 speed pump would be better! Perhaps, $30 run on low continuously, vs. $75/month.

On branding, I have been very happy with the old Hayward equipment I had (20 years old) and the new equipment I replaced it with.

 

[Kaa]

One of the reasons I'm using flex pipe is that the pool is under a deck and I have to route around deck supports -- having a flexible hose helps a lot here.

With respect to the pump, I'll probably get a variable flow version, so high HP should be fine and should make it quiet in slow mode.