Pipes... How big is too big?

[JPRS51]

Working on a re-plumb design for our 30k gallon pool. Installing a new skimmer and moving from 1 return to 3 returns. Pool has no main drain.

With new skimmers having 2" ports, is there any reason to use 3" or 2.5" on the suction line? Seems the 2" port would limit the need for a larger line.

Going to 3 returns, would 2" suffice? Any reason to go bigger or smaller?

 

[jimmythegreek]

2" pipe home runs from suction to all 2" piping on pad. Newer filtera/pumps all have 2" piping and usually come with unions to the equipment. Then 2" out of filter to a 2" manifold with 3 separate 2way jandy neverlubes for each return then becoming 1.5" out of valve back to each return home run. No need for 2" for returns they mostly have 1.5 sockets and with an eyeball they are less than inch opening

 

[mas985]

It doesn't matter the size of the equipment connector, larger pipe will always have lower head loss than smaller pipe. However, there are diminishing returns. At some point the head loss caused by larger pipe will be insignificant compared to the head loss in the other pieces of equipment (filters, valves, etc).