Question on pipe sizing

[cruzmisl]

Sounds good Mark. I'll order a 2" multiport valve then. If it doesn't work I'll just redo it with 1.5" and reducers but I don't think I'll have an issue.

Would the change to 2" have a significant impact on head loss or not really?

[mas985]

If you change both the suction and return sides to 2", I doubt you would get more than 5 feet of head reduction and more likely to be 2-3. You would have to do a full head calc on the plumbing you have to know for sure otherwise you won't really know until you do the change.

[cruzmisl]

I figured as much. It can't hurt to go to 2" so I'll plan on that.

Thanks!!!

[Poolsean]

Did you mean that you're going to replace your Jandy 3 way diverter valve or a sand/de filter multiport valve? Your current Jandy 1.5" valve should also accept a 2" coupling on the outside of the valve for connection to your new 2" pipes, eliminating the need for a new valve. Just cut the old 1.5" pipe flush with the valve. If you're a good plumber, you can peel off the old 1.5" pipe remnant, but that's another post.
I don't think you're going to gain significant flow rates but you will gain some efficiencies by going to the 2" pipes. Your pump will run cooler too, which helps to extend the motor life.