Pex plumbing

[Tim]

Hello again, I am continuing to gather info for the new house,this time concerning plumbing. I had been thinking about the Manablock system,basically a plastic(PVC) manifold known as a "home run" system in which there are seperate shut off valves for every outlet and, I assume, fixture. The piping is flexible Pex tubing,which seems like a good idea,but the Manablock sys. seems to use a whole bunch of tubing. I spoke with a guy from a plumbing supply place today who said that many plumbers today are using the Wirsbo system which utilizes 3/4" trunk lines to smaller manifolds that I assume are located close to the areas they will supply,branching off into 1/2" or 3/8" tubing to supply the end fixture. Does anybody have experience w/ these systems,or can you lead me to a resource for more info,perhaps a newsgroup such as this(I looked but didn't find a plumbing newsgroup) Thanks again for the info. Tim

[RicodJour]

R

[Oren]

I have a Manablock system. The home is 11 years old and not a single problem so far. No leaks/breaks, etc..

Here is enough information to keep you busy awhile (*.pdf library).

[BobK207]

Tim-

I'm an mechanical engineer & avid DIY'r (personally restored a couple older homes)

The "best" PEX layout / installation depends on: the design of the house (ex. ranch vs 2 story; "small" 1 or 3 bath vs 4 or more), location of the water usage points, type of construction (slab, raised foundation) local climate; temperature swings

I've done two home run systems (design & installation) I've done one "remote" manifold system w/ hot water loop (design only)

those plastic "maniblocs" look enticing price wise (the copper manifold with shut off are really pricey but I've used them both times)

I think you'd be very hard pressed to build a copper manifold cheaper than buying one

From your second paragragh sounds like you're on the right track.

the wirbso site has some design manuals to down load

One bit of advice....when building a home run system, even with remote manifolds, smaller fixture supply tubes from manifold to fixture will minimze hot water wait times.

I use 1/2" from manifold to fixtures everywhere, no flow problems & short wait times

Bite the bullet & go copper manifolds w/ shutoffs...you'll be happier

I recommend the cold expansion with PEX reinforcing rings rather than the crimp ring systems. I also recommend the brass Pro-Pex fittings. I got all my stuff online at pexsupply.com (was before locally available at plumbing supply houses)

you can rent a hand expander or buy one on Ebay & flip it

the design guide that Rico suggests is awesome......a lot of info in one reference

cheers Bob

[Rudy]

1.>... manifold known as a "home run" system

2.>..Wirsbo system which utilizes 3/4" trunk lines to smaller manifolds that I assume are located close to

Have #1 PEX system in our current house except the manifold is copper and doesnt have the shut off valves on each run. We have stops in the various cupboards for each fixture. We have one 50 gal Water heater, The pipe is all 1/2" pex, it works fine..can't say I have any complaints.

We had the #2 system in our former house in AZ. The home was 120' "long" and had some LONG plumbing runs. The plumber that put the system in had a lot of experience with Wirsbo pex and recommended it highly. We had a 1

1/4" service after a 3/4" meter. From the 1 1/4, it dropped to 1' pex,then 3/4 then 1/2. NO 3/8 pex, a few of the risers to the faucets were 3/8 though. That system worked great too. We had TWO 40 gal water heaters, I can't say one system seemed any better (or worse) than the other.

I'd either system again.

[Tim]

Rico, Thanks for the link;lotsa good info. I am now thinking of going with the Uponor/Wisbro system and a trunk and branch config. Uses less pipe,better fittings and warranty,and it seems to me one would want shut off valves near the fixture (as opposed to a home run sys) should a leak or problem occur. Appreciate the info man. =20 Tim

[Tim]

Thanks for the opinions and guidance once again,guys. =20 Tim

[BobK207]

Tim-

My home run systems have manifold shutoffs AND fixture angle stops.

In a home run system the PEX is continuous from manifold to angle stop.

I used the Pro-PEX brass fittings..hard to beat those.

Gotta have fixture angle stops....manifold shutoffs are a nice extra feature.

branch and main system has a lot more fittings & connections

Home run only has a connection at the manifold & the angle stops. My

2 bath, kitchen & laundry only had 32 "expansions"

A branch & main will have a lot more and they're be all over the place. Branch & main hot water waits are longer & flow variations can be worse.

cheers Bob