PEX piping

[Ponyboy]

Just looked at a PEX plumbing job which has some interesting features. Below is a manifold for the hot water distribution. Ever seen this one?

Click to Enlarge

30.97 KB

This a a cold water manifold, a little more typical.

Click to Enlarge

29.42 KB

Typical pipe routing and mounting to floor framing and crimp connections.

Click to Enlarge

25.47 KB

The piping is HydroPEX. Anybody aware of any problems with this PEX system? I am always suspicious of the systems with the brass fittings and metal crimp rings. I know Zurn fittings have problems, but I believe they are matched with a different brand of Pex piping. I am mainly concerned about recalls or fitting failures.

[Scottpat]

Those look like homemade manifolds.

The PEX is not supported properly in Pic #2 & #3.

What is in that corrugated line connected to the blue PEX in Pic #1?

[Tom Raymond]

The manifolds are sweet, too bad the rest of it's a mess. What kind of fixtures were there that would require a pressure balance loop (the hot manifold)?

Tom

[Ponyboy]

The corrugated pipe is the flex connector to the water heater below. Also, the water piping supports the BX conduit (right side of picture) for the water heater!

A pressure balance loop? That's a new animal I have not heard of one before. This house is an old craftsman, just remodeled with a second story added. The builder is the seller.

[Tom Raymond]

The hot manifold is a loop, which indicates that several or all of the branches are anticipated to draw at the same time, think multi head shower. The loop prevents one of the branches from being at the end of the manfold and losing pressure as the preceding branches are opened. There will be a presssure drop but it will be uniform across all open branches.

Edit: The loop indicates that someone skilled built the manifolds, obviously someone else ran the pex.

Tom

[Chad Fabry]

A pressure loop at the circuit origin is just dumb. It would depend on all other factors like tubing length, number of bends etc. being equal to ensure equality in volume.

A destination loop, essentially another manifold fed by a single line would be far more effective. Of course sizing the feed larger than the take offs is the easiest thing to do.

[Tom Raymond]

Having the loop at the origin won't do anything for my car wash style shower example, that loop needs to be between the tempering valve and the individual heads/sprayers. It may be there to minimize the pressure differential between the hot and cold lines that can result from not balancing the feeders and take offs or from a large hot water storage tank.

Tom

[Chad Fabry]

I've spent a little time working hydraulics. In my opinion, the loop in the photo is asinine. If anyone can explain any benefit to the construction, other than rigidity, I'm all ears.