Jump to content

New plumbing question. Pipe diameter/restrictions?


Recommended Posts

Is drain capacity determined by the smallest diameter in a system.

Say i run 3 feet schedule 40 plumbing but then use schedule 80 fittings, couplers etc. Would the flow be the same as if id just used all schedule 80? Due to the nominal internal diameter?

Link to comment
Share on other sites

The flow restriction from the fitting will have a larger impact than the difference in diameter. I used furniture grade throughout my system because it had the largest ID available for 3/4" tubing (and it was visually attractive). If you dont have compound angles, bending the tubing is really easy and maintains considerably higher flow. Beananimal has a calculator that will give the exact values for diameter and height differences. 

Link to comment
Share on other sites

^ yup. Any place where the flow in the pipe can become turbulent will cause the flow to slow down. Any joint between fitting/pipe, any corner (90's are the worst). I went a little overboard on my first build, and used a dremel to bevel the ID of all tubes to help ease the transition in/out of all fittings. In hindsight, I wish I'd have just heated and bent the tube instead. About the same work and way better for flow. In the end, however, unless you have very high demands of your pump, or are nearing the edge of how much your overflow can handle this is mostly an academic argument and practical benefits are low compared to the amount of effort on the input side to make changes for theoretical flow improvements. I could maybe gain 5-10% efficiency with getting fancy, or I could turn my DC pump up by a few percent also. Minimal cost difference for the same output at a much lower effort.

Link to comment
Share on other sites

I have a really weird motive which is i want my primary siphon drain plumbing to have a smaller ID from the get go and the emergency drain to have the biggest ID because i intend to run power head wiring through the emergency drain. Sounds insane but it makes for a very clean application. It is a bit harder to service your power heads but i enjoy the tradeoff immensely.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...