sizing PEX water piping system

danster44

I need advice about PEX sizing -- can I expect decent performance using 1/2" PEX for the whole water distribution system, or am I setting myself up for disappointment? The inlet (thru slab) is 3'4" -- I was planning on dropping to 1/2" and running it for the whole system -- the furthest point from the 3/4" supply will be approx 65-70'. Pressure in my tank is about 60 psi (main line from tank to inside stub out is about 100').

Suggestions?

ben's plumbing

hope this helps you ....we have not to many wells in our part of the world but when we do. on well systems we always ran 3/4 main lines hot and cold with 1/2 branches for volume.. 3/4 feeds to hot water tank.ben I really think 1/2 inch would not cut it....

danster44

anybody has bent 3/4" PEX using the metal 90 degree brackets?

If so, is there a "trick" to preventing the PEX from "kinking?"

jimmy21

I'm not a plumber so don't take my advice to the bank but I think you'd be ok running 3/4 as a main trunk line and where ever it branches out to a fixture, run 1/2 from the main 3/4 line.

joecaption

http://www.familyhandyman.com/DIY-Pr...g/Step-By-Step
Look at photo #5.
That's what I've been using for 90 deg. Lowes and Home Depot sell them.

For orginal poster, I'm working on a house right now that someone tryed using all 1/2, at the end of the line the water just barly comes out of the tap, there's so little water coming out of the shower head it's hard to rince off.
There's very little differance in cost between 1/2 and 3/4 but well worth the extra money.
When I redo the plumbing I'm going one step further and using 1" as my main and step down to 1/2 for my supplys.
It's volume you need not pressure really. If there is no volume the pressure will drop as soon as a tap is opened.

plumbing

1/2" goes to all fixtures "toilet,sink,lave,exc.." but 3/4 from main and from HWH "Hot Water Heater" in a line then tie in the 1/2 to your 3/4 line then every couple Joists put a J hook to strap the lines.

Licensed Plumber!

danster44

I've observed and bought some John Guest Speedfit connections for my PEX project -- there's an INSERT in the package (but only 1) for a 3/4 x 3/4 coupler, for example: I did not use it, and have researched it, and apparently the instruction is to use this with JG SPEEDFIT PIPE: OK, what is the difference between PEX and SPEEDFIT PIPE? And if it is an important component, why do they put only 1 in a package that has 2 connections???


My concern is, should I be using this insert, or is it OK not to use it -- my connection is working perfectly "leak free" without the insert.

Anyone in the know, please comment.

joecaption

Just me, but I would have used Shark Bite fittings instead. I've had those cheap plastic ones pop off twice. Once I switched to Shark Bits it never happened again. There also Brass not plastic.

danster44

I'm using a mix -- not using many of the JG Speedfit, cause they're expensive -- I'm actually CRIMPING 95% of all the transitions, but used the 3/4 x 3/4 COUPLER at the inlet, because I will have some changes there (branch to the kitchen sink & dishwasher) and I can unhook and redo when I'm ready --

Just didn't know what to do with the 1 INSERT in the package, so I ignored it.