Thread: Pex Manifold

Plumbers have just started using PEX in my area and I have only come across it a couple of times. The house today did not have a manifold and I cannot find anything that says it has to be there.

Does it?

If not what are the benifits for having it?

Thanks

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Originally Posted by Gregg Austensen

Plumbers have just started using PEX in my area and I have only come across it a couple of times. The house today did not have a manifold and I cannot find anything that says it has to be there.

Does it?

If not what are the benifits for having it?

Thanks

A manifold is not needed. They are a nice addition. They reduce the number of splices and connections. With a manifold you will have a dedicated line to the fixture.

Pex manifolds are nice for the end user but are a terrible waste of piping. Say you have your manifold 100 feet away from the master bath. Instead of having two main hot/cold lines run 90 feet, then the rest consists of pipes branching off it, you'd have 100 feet for the toilet, 200 feet for the tub, 200 feet for the shower, 200 feet for each sink, etc.

Why couldn't you have a second set of manifolds at the bath?

Originally Posted by Thom Walker

Why couldn't you have a second set of manifolds at the bath?

Access.

For more info on designing PEX systems:
http://www.toolbase.org/PDF/DesignGu...esignguide.pdf

This stuff has pretty flexible design options. One is a remote mainfold system. If the manifolds are adjustable, an access must be present. If they are flow through they may be enclosed.

Originally Posted by Joshua Hardesty

Pex manifolds are nice for the end user but are a terrible waste of piping. Say you have your manifold 100 feet away from the master bath. Instead of having two main hot/cold lines run 90 feet, then the rest consists of pipes branching off it, you'd have 100 feet for the toilet, 200 feet for the tub, 200 feet for the shower, 200 feet for each sink, etc.

Now Joshua, you are sounding like a builder! If I recall a similar argument was made by builders over the requirements for the instillation of EIFS!

The manifolds have been proven to reduce the number of leaks by reducing the number of connections. Less connections equals less leaks with this type of system.

My home has a manifold. Everytime the kids are outside playing with the hose, I thank the plumber as I shut the water down for that hose bib.

Originally Posted by Scott Patterson

Now Joshua, you are sounding like a builder! If I recall a similar argument was made by builders over the requirements for the instillation of EIFS!

The manifolds have been proven to reduce the number of leaks by reducing the number of connections. Less connections equals less leaks with this type of system.

ssshhhh... I am a builder. Well, a plumber anyways. I'll put in whatever the homebuyer or contractor pays me to put in.

I'll never argue that fewer connections in a system results in fewer leaks, in any kind of pipe: Copper, pex, quest, cpvc, etc. But I do wonder, how these leaks happen, and why didn't they show up during the air test?


Manifolds are a great convenience for the homeowner, but if they're building the house new they should realize all the extra time and money it takes to do it properly.

Originally Posted by Joshua Hardesty

ssshhhh... I am a builder. Well, a plumber anyways. I'll put in whatever the homebuyer or contractor pays me to put in.

I'll never argue that fewer connections in a system results in fewer leaks, in any kind of pipe: Copper, pex, quest, cpvc, etc. But I do wonder, how these leaks happen, and why didn't they show up during the air test?

Some reasons that I have discovered that the leaks do not show up during an air test is that the water weights the pipe and adds stress to the connection points. This happens more with PEX or CPVC. When a fixture is turned on & off the pipe moves, one of the reason the pipe is not to be be taught in the walls. It needs to be able to move.

Trash, burrs, in the lines can also clog up small areas that will leak, then when the water washes over the area and removes whatever is clogging up the area you have a leak. Air will not do this, but the water moving through the pipe will.

I have yet to see a main manifold for this stuff, but I have seen a hot/cold line set connected to a "bathroom" manifold. This is a small manifold usually located in the attic space above the bathroom. Off this branches supply for the fixtures. Pretty neat...if they would only follow the instructions.

Here you go........

Thanks Victor, I meant to say I have yet to see a main manifold on an actual inspection.
Thanks