I want to make a home run line of 1/4″ pex about 70′ from the hot water to the shower. Will that flow enough to run a shower? I want the smallest line so I don’t waste too much water purging the cold from the line.
Eric
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Replies
As a roll of 1/4" pex costs
As a roll of 1/4" pex costs about $20, do this:
Buy a 250' roll. Attach one end to your supplies temporarily. Connect the other end to a cheap shower setup, with a mixing valve and shower head.
Turn it on and see how it works.
BTW, I think you are thinkin of 3/8" PEX which is 1/4ID.
Code Requirement is:
That, the line deliver 3-gpm at 20-psi.
You need to determine the minimum static pressure, and do the pressure loss calcs for 3-gpm over the 70-foot run length.
A quick look at an online table shows a drop of 0.39psi/ft of length. So you would drop 27.3 psi in your 70-ft run.
Which means you would need at least 60-psi as an inlet pressure to provide a bit of a margin of safety.
Just checked the Zurn site. They are listing a pressure drop of 52.4-psi/100-ft at 3-gpm. So, that would mean a drop of 36.7-psi in 70-ft. This is for straight runs, any fittings or bends will increase the loss. They also indicate the velocity is at 9.9-fps, and some local codes are limited to 8-fps maximum.