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PEX Cold Supply

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Jun 14, 2013, 07:05 PM
PEX Cold Supply
I am converting my plumbing to PEX and I am planning on using a manifold where each fixture has its own supply line. However, if I have a cold water supply going to a vanity sink in a bathroom, can I supply the toilet with a simple t-brnach off of this cold water supply. Or does the toilet need to be on its own supply line?
Jun 14, 2013, 08:40 PM
it is code. and commen seince to have a seperite cut offs for each fixture. if ya gotta work on it, ya dont shut down every thing
i personally like a cut off under the sink and toilet
also. what size line are you running to your sink? 1 fixture per 1/2" line 2 fixtures is a 3/4 line
thats so you can use both fixtures at the same time with no low flow condition*****?v=vn7bkncf1_E
Jun 20, 2013, 02:52 PM
The short answer is:yes you can
The correct answer is: no you shouldn't, because you will defeat the purpose of the manifold system.

Being able to isolate each fixture is key, and you won't have any T connections behind your drywall to leak. Also, toilets usually require more maintenance than lav's, and a separate shut off at the manifold will be appreciated when you need it.

You can save $$ by running 3/8" line to toilets, lags, and ice makers. Use 1/2" to all showers, tubs, laundry, and hose bibs. (assuming you run dedicated lines to each) if you have multiple shower heads in the shower, use 3/4" line.

If you haven't installed your manifold yet, use 1" suppy lines into the manifold.

If you over size the supply lines to fixtures, it will take far longer for hot water to reach the faucet. A 1/2" line has twice the volume of 3/8" line. The fitting on the sink is 1/4", so you'll still have plenty of pressure and volume.

Good luck!
Jun 27, 2013, 08:26 AM
wrong!!!!! 1/2" is minimum size piping as per code and a shut off valve SHALL be used at each fixture
page 40, section p.810-3 valve locations

This message has been edited. Last edited by: Frodo,*****?v=vn7bkncf1_E
Jun 29, 2013, 08:28 AM
And when you think about it the savings would be minimal at best. Or may ever be more expensive as buying two sizes instead of all 1/2" fittins might mean buying single packs of PEX fittins instead of bulk packs. Sure you will always find a use for 1/2" on future projects.

Popeye only reached for the Spinach can as a last resort...