Plumbing question

[iGotJokess]

I keep seeing post about head pressure and to try and avoid 90’s for my return, is this also a rule of thumb for my drain lines? Unless I’m missing something, which is possible, would 90’s matter on my drain lines? Running bean animal style

 

[Hydrored]

I don’t think it matters since to have a gate valve anyways.

 

[jrlg]

a 90 in the drain line will slow the water as slight resistance but nothing near the decrease in head pressure when pushing water up. the rules of drain lines are no ball valves on the emergency line, no kinks and overall best design to avoid clogging. and best to have it a larger diameter than the return line. I used a gate valve to sync mine in using 2 x.75 for return and 2 x1.5 for draining