OK, I need to re-plumb and replace some old ball valves. I have 1.5" black rolled tubing connected to 1.5" pvc which comes out of the ground. I have a main drain and two skimmers which will be "T-eed" and run to my pump basket with one 90 degree turn. There will be about a 18" of straight pvc before it enters the pump basket. Currently all the pvc is 1.5".
I have ordered three Pentair 1.5/2.0 diverter valves. As I understand, I could use 2" pvc on these valves and use an adapter to connect to the 1.5" pvc where it enters the ground. I could then use 2" pvc pipe and fittings all the way to the pump.
Since I have 1.5" tubing coming out of the pump to the return lines, is there any reason to go with the larger size pvc on the intake side?(edit) I could also run 2" from the the pump to the filter and back to where the return line enters the ground. Of course the filter multi-port valve is 1.5" so it would restrict the flow. Since it will be entering a 1.5" tubing back to the pool returns, is there a good reason to increase the size?