Re-plumbing - sizes?

[samtex]

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?

Samtex

 

[tmobileguy]

I would go with 2" PVC. With all the twists and turns of pad plumbing, the larger diameter will allow you to move more water especially on the suction side where you can combine the 1.5" pipes to a 2" pipe right to your pump....