When is a plumbing home run a home run?
We are building a new home and are doing the plumbing supply lines with PEX tubing, a manifold system, and home runs from the manifold to each individual fixture.
The plumber has run the PEX lines, but was unsure where to mount the manifold in the mechanical room. So to save PEX tubing, he cut the PEX short, and plans to splice on whatever additional length is necessary to reach the manifold.
I thought a plumbing home run was a single, uncut length rom the manifold to each fixture. No joints in the PEX line means less chance of a leak at a joint. The plumber claims the single line may include one or more splices, and that splices are failsafe. Should I be concerned about splices in the PEX lines?
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Replies
Roger,
I wouldn't worry about the integrity of the PEX couplings. These couplings are just as likely to remain watertight as the connections between the PEX tubing and the manifold, or the connections between the PEX tubing and the remote fixtures.
I understand your point -- uninterrupted PEX runs would have been preferable, both aesthetically and as a matter of a worker's pride and sense of craftsmanship. But there are lots of things to worry about when you build a house -- as you well know -- and I would let this issue go if I were you.
Roger, not much I can add to Martin's sensible advice. There are several types of pex connectors, some of which restrict the flow more than others, but none significantly enough to cause concern. In a typical pex installation for a house using crimp fittings it is not unusual to have up to a hundred joints. I've never had a leak.
I incorporated a Homerun/manifold system when I built my house.
At the time it seemed to make sense.
If I had a "do-over" I would follow Gary Kleins strategy.
http://www1.eere.energy.gov/solar/pdfs/sda_saving_water.pdf
As far as I'm concerned, a plumbing home run could be done in copper, with couplings and elbows along the way. The "home run" part refers to the fact that the line comes from the source without branching off, and the fact that you can shut off each side of each fixture individually without impacting any other fixture.
As far as why the plumber didn't know where to mount the manifold when he was roughing in... that question goes straight to the builder. Don't make him guess or you get what you got.
John,
After reading Gary Klien's presentation I'm not completely sure what his strategy is. It seems to me he advocates hot water distribution system that is a looped trunk and short small branches all insulated and that the loop should be recirculated "on demand". He doesn't mention the cold water distribution, but I assume it's trunk and branch without a loop back. I'm unsure how the recirculation can be "on demand". Gary's data on the energy use of a temperature controlled recirculation is discouraging as I can see how to do that.
Jerry,
Q. "I'm unsure how the recirculation can be 'on demand'."
A. There is equipment that makes the magic possible. For more information, see Hot water circulation loops.