I am replacing some of the old galvanized in my home with PEX. Does anyone see a benefit (better flow rate, etc.) from using a manifold layout or should I just follow the original pipe route to save the cost of the manifold and extra tubing? Most of what I need to replace is easily accessible in the basement.

Also, one installation guide recommended using 3/8" branch lines instead of 1/2" so you waste less water waiting for the hot to get to the faucets. They claim the loss in flow is minimal. Do you find that to be true or do customers complain if you use 3/8"?

i would never ever in my life even think of using 3/8" pex pipe. those that have suggested that would pipe a 2 1/2 bath house with 1/2" copper from the meter also. it may work but not nearly as good.

the cost of the pipe is next to nothing so that should not even be a factor, what will be is if you have a recirculation line or not. they dont work very well with the manifold/home run method unless it is ran a certain way

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Use 1/2" . Pex NEEDS to be oversized, the i.d of the pipe is smaller than copper/CPVC. Personally I dont like the manifold system unless its for a Hotel/Motel/Apts/ect. A recirulation line is also a nice addition

i like the manifold system. with a 1" manifold and 1/2" lines, you can turn on multiple faucets and see almost no change in volume.
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Yea, looks nice packy. The PRICE increases when you use a manifold system and most of the time its looks horribal when finished. Spaghetti anyone!



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Piped correctly WITHOUT using the manifold system you can also turn on multiple fixtures without a noticeable pressure drop.

Looks good Packy, How do you make your manifolds?

I usually use branch method, but if I could make one look that good, I might think about trying it your way

oh, that was just something i threw together in my spare time..
just kidding.
watts make them a few different ways. 1" copper with sixteen 1/2" branches with mini ball valves costs about 10 bucks a branch.
you can't make one for that price.
you can cut them into any number you want or buy them in various outlets.
page 8 in their catalog...
[www.watts.com]

In a small home I just do trunk and branch...
Larger ones I'll do trunk and branch using remote manifolds. See page 30 at the link below...

[www.huduser.org]

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i just don't like the idea of a manifold behind an access panel upstairs somewhere.
i've done it with hot a few times. not because i prefered to but because i had to in order to recirculate.
the last few houses i've done have had open floor plans. no interior partitions to run water line and big engineered beams that can not be drilled.
snaking around a bunch of 1/2" pex lines is much easier than trying to get a couple of 1" lines and manifolds in.
architects make our life miserable, sometimes.

quote; architects make our life miserable, sometimes.

Just "sometimes", I thought it was their mission statement. Otherwise why would they put bathrooms over the center of a ballroom sized dining room, or offset partitions on each floor? Or as one school in Illinois, show a mechanical room, but when the building was constructed as per plans it did not exist and they had to build one outside and run all the piping to it.