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Do Extra Copper Elbows Restrict Water Flow?

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Larry

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Oct 22, 2003, 3:24:03 PM10/22/03
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I'm replacing the wallboard and tile in my 3/4 bath's shower. The 43
year-old plumbing is 1/2" copper pipe. The hot water supply comes
straight up out of the concrete slab, into a Tee, over a foot into a
90 degree elbow and up about 4 feet along a stud into the bottom of
the shower valve assembly. Very neat and straight. The problem is
that to make it this straight, the original plumber had to run the
copper pipe in front of the 2" steel vent pipe between the Tee and the
wall stud. The vent pipe is almost flush with the wall studs.
Because of this placement, the copper pipe sticks out about a quarter
inch beyond the wall studs. I guess they either hollowed out part of
the wall board to accomodate the pipe, or they didn't nail the wall
board all the way against the studs. The old wallboard is too far
gone to tell for sure.

I want to replace the shower valve assembly and the hot water supply
pipe to it because of its age and the fact that it's really green.
I'd rather run the new copper pipe BEHIND that steel vent pipe so I
can nail or screw the new wallboard (durock) flush against the wall
studs. The only way I can see doing this is by adding 3 or 4 more 90
or 45 degree elbows to the copper pipe so it will go around the rear
of the vent pipe and then up to the shower valve assembly. Or
possibly bending a curve into the copper pipe, which I've never tried
before.

I know the more connections in a copper line, the more the chance of a
leak. But I'm fairly good at sweat soldering. What I want to know is
if the extra elbows in the supply line will cause any restriction of
the water, vibrations in the pipes or other problems when the shower
is turned on.

Randd01

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Oct 22, 2003, 3:42:52 PM10/22/03
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See if you can rent a manualpipe bender and bend it around obstructions
instead. Are you sure the pipe won't push in a bit when you put up the Duraroc
instead of going thru all that trouble?

Speedy Jim

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Oct 22, 2003, 3:46:35 PM10/22/03
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The amount of pressure/flow loss feeding just the shower will
be negligible. 45's are better than 90's.

If you get a length of soft Type "L" copper tubing, you *can*
bend it to suit instead of using fittings.

Jim

Paul Franklin

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Oct 22, 2003, 6:35:51 PM10/22/03
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On 22 Oct 2003 12:24:03 -0700, jum...@hotmail.com (Larry) wrote:
<snip>

>I know the more connections in a copper line, the more the chance of a
>leak. But I'm fairly good at sweat soldering. What I want to know is
>if the extra elbows in the supply line will cause any restriction of
>the water, vibrations in the pipes or other problems when the shower
>is turned on.

Yes, each elbow will restrict the flow somewhat.

In a shower, however, the flow is most likely going to be more
restricted by the low flow shower head or shower valve. I doubt 3 or
4 more elbows will matter, unless you have very marginal flow and/or
pressure to start with.

Plumb it the way you want it, then test it before you close up the
wall, which is a good idea anyway in case you find a leak.

The extra elbows won't cause vibration problems as long as the piping
is clamped to the framing properly.

Oh, one more thing. Some of the new shower valves allow you to
reverse the hot and cold inlets (for so-called back to back
applications) by removing the cartridge, rotating it 180 degrees, and
reinstalling.

Sometimes that makes the piping simpler. When I reverse one, I write
hot and cold on the appropriate pipes with permanent marker to save
some headscratching for someone in the future.

HTH,

Paul Franklin

Larry

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Oct 22, 2003, 10:22:49 PM10/22/03
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ran...@aol.com (Randd01) wrote in message news:<20031022154252...@mb-m15.aol.com>...

> See if you can rent a manualpipe bender and bend it around obstructions
> instead. Are you sure the pipe won't push in a bit when you put up the Duraroc
> instead of going thru all that trouble?

Nope, the copper pipe is running horizontally and it is right against
that vertical 2" diameter steel vent pipe. It won't push in even a
millimeter where the vent pipe is, and the vent pipe itself won't
move. Bending a curve into the copper pipe might be feasible, though.
Does this weaken the pipe and shorten its lifespan?

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