PEX (plumbing) questions

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mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

I'm in the process of assessing a project for replacing all my plumbing with PEX and have a few questions that I have been unable to get clarification on from reading previous postings here.

1) Can I used PEX to connect up directly to my hot water heater (tank), or do I HAVE to have copper flex lines? (Finally had an electrician wire up a circuit for an electric HWH to replace my old propane one!) I see that there are copper flex lines that PEX can connect to; just seems a bit redundant in that PEX flexes.

2) Which connector rings are best, clamp or crimp? I notice that there are crimp rings w/plastic on one end that are supposed to be easier to handle and position for crimping, anyone use these?

3) While I plan on having shutoffs at each fixture, I'm also desiring the function of a manifold in being able to isolate an individual line (home-run layout/config). My concern is that the most efficient location might not be all that accessible, it would locate the manifold in a pocket where the HWH is (see https://www.mobilehomerepair.com/phpbb/v ... f=6&t=8275, which is accessible via a removable panel inside the master bedroom closet. Should I be concerned that this is not a real easy place to get to? I'm not thinking that I'd need to access it unless I encountered a problem with one of the water lines.

4) In one thread I read someone recommended running 3/4" lines to outside faucets. Given that manifolds tend to have 1/2" outputs, would it really be worth it to increase from 1/2" to 3/4"? I'm kind of thinking that I might want to just tee off of the incoming line (after a main shutoff) and feed the outside faucets directly instead of trying to route them through a manifold (otherwise I'd be looking to size up on the manifold- $$). NOTE: I've got a well pump and pressure tank, not a lot of volume to begin with.

5) How do you hold any fixture shutoff valves aloft/off the floor/cabinet bottom? Is it possible without using some sort of line clamp (avoid having to cut into the belly wrap and tack some sort of clip)?

6) Should I look to run lines as direct as possible, or is it advisable to route them (kind of bundle together as much as one can)? Trying to route things together seems like it might make it easier to know where lines are running in case you're doing any cutting or nailing from above or below.
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Greg
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Location: Weedsport, NY

1- I don't believe there is a code regulation that requires Copper flex lines from the tank. I believe the flex is intended to make connections to the tank easier should the line ups be slightly off.

2- Clamp/Crimp. This debate has been going on, I think it seems to be an East/West answer. I have used the crimp rings with no problems and never have used the clamp type (why change what works?). JD uses the clamp type and has not had ant problems. So, I guess buy what ever type you feel like using.

3-The manifold system should work fine anywhere you mount it. As you said the only time you should need to get to it is if you have a problem with the line. You would be fine "bundling" The lines together.

4-The larger the lines you run, the more VOLUME you will have, the pressure will remain the same. You could tie the outside faucets directly to main line with no problem, don't forget shutoffs ahead of the faucets.

5- If you are changing the system to a manifold type you will almost have to open the belly up to run lines etc. I usually attach the lines to the walls under the cabinet for support.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

Greg, thanks for the input!

Yes, the shutoffs on the outside faucets! I had a mental note to do this.

Regarding the attaching of the lines under cabinets, are you saying that you run the lines back against the wall? What do you use to anchor with? (would like something that looks good) Right now everything comes up about 1/2 foot from the wall.

Oh, no real need to open up the belly, as it's pretty much already opened up (see pic)- that was a project in itself, one that had prompted me to push up the schedule of replacing the plumbing to take advantage of that work (why crawl under the home more times than necessary?) :-)
P8250051 (Medium).JPG
Please note that this is the state of things as I'd found them when I bought this place.
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Greg
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You can attach a 1x against the back wall and screw a clamp to to hold the pex in place. I have seen plastic clamps but conduit clamps would also work, you may want to wrap the tube with tape to prevent any rub damage.

The belly may not be as bad as it looks. It looks like most of it is there and may be repairable with belly tape.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

Any ideas on dealing with the lines to toilets? These are out and naked...

Yes, I'm HOPING that the belly is not as bad as it looks (clearly folks who tried to close it up didn't have a clue about using the right materials!). But... that big blue tarp is lurking... If there's anything that I've learned is that everything seems to require maximum effort!
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Greg
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For the toilet supply you could use a chrome supply line from the tank to the valve. Keep the valve floor level with a chrome flange that would stiffen it up above floor and still have extra PEX below the floor to pull the valve up after you remove the solid line from the flush valve.

Greg
"If I can't fix it, I can screw it up so bad no one else can either."
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

Greg, you always have good answers/solutions! Thanks!

Ran across a couple of bits of info (from PPFA http://www.ppfahome.org/pdf/PEX%20Handb ... v_2008.pdf) as pertains to my questions/concerns:

Manifolds shall be installed at
least 36" away vertically, or 18" away
horizontally from the water heater. A
manifold for cold water only may be
installed near the water supply.


This one is a concern for me because I've got a really limited space in my HWH closet. Further reading seems to suggest that the issue pertain to dual port, plastic(?) manifolds, and that it's not an issue with copper manifolds (which I'm going to go with- four and five port units [like this: http://www.pexuniverse.com/store/catego ... -open-ends] in a remote manifold configuration). But... I still don't see there being any issue with plastic manifolds either; that is, what kind of heat would be generated OUTSIDE of a water heater that the manifold itself wouldn't be experiencing through normal operation (water temps are likely higher than the ambient air temps from the water heater in proximity!)? Well, for electric water heaters I can think of no real reason: for gas, yes, because of flue temps.

If anyone knows otherwise I'd really like to hear before I get to settled on the layout.

Do not use in applications where
the temperature of the water could
exceed 180o F at 100 psi unless specifically
approved in the code, e.g.,
water heater relief line. See
manufacturer’s recommendations for
higher operating temperatures at lower
pressures.


I was interested in this because I was curious whether I could use PEX for the HWH relief line. Currently I've got CPVC for this line. CPVC is only rated up to 200 degrees. Interesting when relief valves set to trip off at higher temps(? pressures, which would be increased by increased temps). PEX also is stated as being able to withstand 200 degrees, though not in a sustained manner. Most info seems to suggest that this issue is mitigated by the fact that this line isn't under pressure.

So, anyone know why PEX can't be used in this application? If not, then is there any limitations such as having some slight bends (for routing) in such a line?

And now for a couple of new questions...

1) Is it true that 3/4" lines are required for multi-head shower heads? I've got one that can operate the main head plus a hand-held head. I don't need both heads operating: though once in a while my wife and I would like to use them when we shower together.

If this is the case (3/4" required), can I (using an adapter?) just run 3/4" lines out of a manifold with 1/2" ports?

2) What are people's thoughts about PEX-a? This utilizes a supposedly more uniform (in integrity) pipe that is connected to fittings via a stretch-on method. It's also able to take tighter bends. (reference: http://www.uponor-usa.com/Header/System ... ained.aspx issue for me is that there's a limited variety of manifolds available [I see 1" in what I would need, but not 3/4"]).
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

A follow-up... Gee, I'm starting to feel like I'm talking to myself here (only my wife and dog are exposed to the real thing :lol: )

I was able to discover that the proximity issue/question doesn't have anything to do with thermal issues; it's more about just what one would expect- flex*, and the codes just really haven't been updated to reflect PEX (perhaps the flex connector lobby is strong :lol: )

* The code says minimum 18" and a maximum of 24". I suspect that anything longer would present an issue of load/sag.

Cannot find anything on the relief drain issue/question, other than it's specified under section 54: 10.28.3 of the NFPA. Sigh, in order to discover what laws we're governed by we have to PAY for the publications(s)! Since CPVC is currently installed (and I suspect that this was code) and CPVC is rated to 200 degrees as is PEX, then I see no reason why PEX cannot be used: and, this temp rating is under pressure.

Does anyone know whether the relief drain can contain any bends (PEX)? Just wanting to understand what options I might have.

And about the issue of supporting PEX out of the floor- Escutcheons! (example (not an endorsement of product): http://www.pexsupply.com/Wirsbo-Uponor- ... 6-OD-White)
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

I'm back to my plumbing job research... for some reason I'm unable to get the Forum's Search function to find any hits for "PEX" (not even for a thread that I started!) So... more questions...

Do folks who install PEX secure the tubing underneath (tack to joists for runs) or just let it hang within the belly wrap?
bobfather99
Posts: 195
Joined: Fri Nov 13, 2009 2:09 am
Location: Indiana

I wouldn't let it hang down. Tack it up above the belly insulation to keep the pipes from freezing up, plus it keeps anyone from cutting into the tubing if they're cutting the belly open for some kind of service(or to remove a dead "critter")
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JD
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You shouldn't use standard metal conduit hangers on PEx. Nothing with a sharp metal edge. Plastic straps made for PEx is best and cheap. Straps need to be every 32" when hung below or beside floor joists. You can go up to 72" when the pipe is on a flat supporting surface.

Other key points would be to install all of the pipe loose. Loose/movable inside the straps and on long runs you should install a loop or a good bend in the line to offer slack when needed. Keep PEx away from any heat source and use metal plates to protect the pipe within joists and studs.

I don't have a lot of experience in installing manifold systems, but the ones I have done was very straightforward and easy. Here is a link to a good install overview that covers straight runs and manifold systems. It is for Zurn PEx, but the same guidelines will work for other brands.

http://www.zurn.com/operations/pexrh/pd ... lGuide.pdf

I hope this helps
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Today is PERFECT!

All information and advice given is for entertainment and informational purposes only. The person doing the work is solely responsible to insure that their work complies with their local building code and OSHA safety regulations.
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

JD, thanks for the input.

Here's what I found from Uponor's Aquapex Installation Guide on this subject:

Along horizontal runs, install supports every 32".
If horizontal runs are continuously supported
(truss-to-truss), install a tube talon every second
or third truss. Follow local code requirements when
installing PEX tubing in fire-resistive construction
floors, ceilings, or walls.

Wasn't sure if MH installs were treated the same... Though, however, I'd already had tube talons budgeted for.

I guess I was just looking for some way out of having to hack the belly wrap more than it already is :-()

I've decided to utilize a remote manifold design (after mulling the other designs). What made it was easier to go this route was Uponor's ProPex manifolds (example: http://www.pexsupply.com/Wirsbo-Uponor- ... -2212000-p); they're pretty flexible in that you can connect them together, make them pass-through and or close ended. NOTE: Yes, this means that I have to go with all Uponor stuff, as it's PEX-A; after reading about all the different PEX tubing types and fasteners I feel more comfortable going with PEX-A (yes, it's a bit more expensive, but I expect to have to live with this stuff for a LONG time).

I'm pretty much down to figuring details for outside faucets and shower/bath connections. It's a lot more critical with PEX-A since I can't just run down to the local Lowes or HD to fetch stuff that I didn't account for.
dedou
Posts: 60
Joined: Fri Aug 12, 2011 6:25 am
Location: Central Vermont

Mdnagel, I'm hoping you will/are taking lots of photos to share? I'm really interested in
PEX as well, and am planning this year to do something like DCdiva did and bring our
plumbing up into our single-wide and use PEX all the way. We have to repair/replace a
good part of our floors, so might as well do it all at once, finances allowing. This is an interesting thread, thanks!
Devon
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mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

Devon, will do what I can with pics, but it's sometimes a bit hard when you're in the thick of things. And, mostly it'll be routing lines underneath, where things are a bit difficult to really see. Probably the most interesting aspect would be the manifolds and some of the end-point connections. Most folks would probably be doing PEX-B, as it's available in your local big box stores; PEX-A is only (that I am aware of) available on-line, and it requires special tools which are expensive to purchase (rental appears to be about $40/day)- this presents an issue in that one should probably have tools available for any changes/repairs (there are manual tools [expanders], but they're still running in the $125-$150 range, used!).

Key is to settle on the design. Check out the link that JD was kind enough to supply.
mdnagel
Posts: 187
Joined: Thu Jan 06, 2011 12:39 am

Just an update on my planning...

I'd been mulling over having two locations for manifolds, with two 3/4" lines running a cold and a hot to the other set of manifolds. The IDEA was fairly elegant because I'd be spanning a run of 20' between the two areas with only two lines. But... one area where I'd be best placing manifolds for servicing one area would be a bit busy -laundry room, I'd likely end up really having to cut up a wall where the main shutoff is located. I was getting close to accepting this as the design until I started thinking about having to run the water for quite a while on the remote end of the hot water supply. With 3/4" line I'd be having to push through 1.46 pints MORE than with 1/2" (direct service line). So...

I'm now thinking about locating all the manifolds in the HWH closet. It'll cost me about $40 more in tubing (hangers not included), but it'll cost less for installation of the manifolds all in the HWH closet. I'll also have to make a new drip pan fit in there with all the lines running through the floor: floor space will start to get a bit cramped. Attaching a picture of inside my HWH closet looking down at the floor area where the lines will route through, below where I plan to mount the manifolds.
P1070741 (Small).JPG
In the upper right in the picture is the new electrical circuit installation. Gas HWH will be removed and replaced with an electric one when I do all the plumbing work.

Would like to know if anyone has used pex for the safety valve and drain (pan) lines (two separate lines).
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