PVC to PEX, pipe size question


Old 11-25-15, 03:11 AM
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PVC to PEX, pipe size question

My small house has 1/2" PVC piping. Some of it runs under an addition built over a slab, and these pipes have frozen in past winters. We want to re-route these pipes up into the house, using PEX. The new PEX line will service bathroom and laundry room, so I've been looking at installing a 3-port open manifold in the new PEX line. The problem is that the manifold sold at Home Depot and Lowes reduces from 3/4 in. at the 2 inlets to 1/2 in. at the 3 ports. I would need 1/2 in at the inlets as well at at the ports, because my PEX line is 1/2" throughout.

When I did an internet search for a manifold that has 1/2" inlets as well as ports, I didn't find anything. I suppose I could use 1/2" to 3/4" adaptors at the inlets on the manifold, but my question is, is that asking for trouble?

I realize that many pipe systems start with 1" or 3/4" and reduce to 1/2" nearer the fixtures, but this is a small house and it is 1/2" pipe from the water meter.

Does anyone see a problem with using size adapters on each side of the manifold? Could this cause water flow problems? I don't think so but I thought I should ask before going ahead and finding out the hard way.

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Old 11-25-15, 03:25 AM
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There won't be a problem with using the adapters. The bulbous part of the manifold is closer to 1" anyway, so even though you don't have the ideal set up, using the adapters seems like your only choice.
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