Need Help Pex Plumbing

16 years ago

IÂm thinking of re-plumbing my potable water needs with a PEX system. I have an aggressive water condition that is pitting my copper pipes (22 year old home), plus my water pressure isnÂt the greatest. IÂm currently afraid to try and increase the pressure with thin (schedule M) pipes that tends to pit as it is.)

My plumbing skills are limited- I can solder, however if IÂm going to replace the copper- I donÂt want to use copper again even with a better (thicker) pipe since eventually they will leak again- plus, I donÂt relish the thought of soldering in tight places.

Everything IÂve read about PEX seems to work for me. It will not be affected by the aggressive water, and can be easily installed. (I do have some concerns about mice eating at the PEX??)

My first set of questions regard the different methods for joining the tubing to connections. ItÂs my understanding that the different systems are unique and must be used consistently. I was thinking of using the Wisbro system of compression and expansion. Does one tool do both? Can it be used in relatively tight spaces (under sinks)? Do I have to get special PEX tubing for this system?

My current game plan is to modify my current copper plumbing with PEX. I have a two story home with an exposed basement ceiling. I can clearly see where the Â½" copper pipes branch off the Â¾" main to the separate sites of the kitchen and Â½ bath above on the first floor. I am considering disconnecting and sealing off the current Â½" pipes that feed to the kitchen and re plumb PEX from a manifold to each fixture using the same holes through the floor above. The Â¾" copper would then be connected as a separate line in the manifold as well to continue to supply water to the second floor.

The reason IÂm not thinking of redoing the 2nd floor plumbing immediately is because it presents some major obstacles for my limited plumbing and carpentry skills. The current pipes are hidden in the walls and ceilings, and I donÂt know exactly where they are.( Ideally if I knew where they were I could cut them out and replace them with PEX tubing, fishing them through the same holes in the walls and joists.) Instead IÂm considering a new route maybe through closets etc. to reach the upstairs fixtures.

Any and all suggestions are welcome.

Thanks,

Don

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Comments (21)

lazypup
16 years ago
If your reason for replacing the copper is due to aggressive water PEX may not be the best choice because all the end terminations on a PEX system are made of the same grade of copper as the copper pipe, thus a PEX system is vulnerable to the same types of problems from aggressive water as is a copper system.

A better choice would be to use CPVC which has no copper components in the system.

One the other hand, in my humble opinion, if you have aggressive water that is eating up your pipes, what is the long term health problems associated with that water. I would much sooner look for a water treatment system that would eliminate the water problems rather than seek a pipe material that might be more tolerant.
donmorgen
Original Author
16 years ago
Lazypup:

Thank you for reply and concern. First off my water is fine for consumption, it's just that the particular water chemistry is slightly aggressive to copper. It's really a combination of many factors (ph, temperature,dissolved solids,calcium ion concentration, and thin copper pipe).

Regarding the fittings being made of copper. That will not be a problem for many reasons, but primarily because all my pipe failures have occured where the pipe is horizontal. I have never had a failure on vertical pipe, nor at any terminations.

CPCV would challenge my plumbing ability more that PEX.

Having heard my response, can you help me with my specific questiona regarding the pex tools, and my plans to re plumb?

Thanks,
Don
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I didn't want to bog down my post with too much information, but to clarify, I added a 40 Imp. gal Giant brand (made in Quebec) electric water heater in series to the 75 US gal Marathon water heater I spec'd for our house, completed last year. The 105 gal Marathon I initially calculated would be enough for us is not available in Canada. The 75 US gal Marathon is mostly adequate, but the Mrs. wanted a greater reserve capacity, so I am experimenting with this set up. We have 43F incoming water temps in winter. In a few years I want to finish the mechanical room, and then I will buy a second Marathon tank. We have very hard water, 36 (thirty six) grains, with a 70,000 grain softener. I want Marathon tanks due to their polybutylene/fibreglass construction, so no need for a rapidly consumed anode rod, nothing to rust. I know this steel tank won't last long with my heavily softened water, so I just bought a standard tank to see if this combo makes the Mrs. happy. So yes, I placed 3/4 PEX onto a PEX/FIP adapter directly onto the hot water nipple of the Marathon tank. The 18 inch copper stub you speak of is needed for gas water heaters, because of the hot flue right next to the pipes. My Marathon set up from the plumber had 2 BrassCraft flexible copper lines from the nipples to 3/4 PEX that runs throughout the house. We have a recirc line, 3/4 PEX not 1/2 for some reason piped to a Grundfos recirc pump that is plumbed into the drain port of the Marathon tank as per Marathon's recommendations. I removed one flexible copper line to connect the hot Marathon port to the cold Giant port. I thought of installing copper stubs with unions on the Marathon tank, but I had left over PEX so I used that instead. So my number 3 question is can I reuse the flexible copper water heater connector if I choose, or is the crushed copper ring next to the rubber washer a one time only item? If so, are these copper rings available separately? Thanks.
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I have to agree with Jake on this one, that first response sounds like a bunch of hype to me. Let us review the facts: Both PEX and Copper provide an very good system however the aforementioned statement that a PEX homerun system saves water, Maybe it does, but then maybe just the opposite is true, depending upon the layout. Consider this, if you have a Main and Branch layout the lead time to get the hot water from the tank to the fixture will remain equal. On the other hand, if you have a manifold and home run system it is true that the smaller lines contain less water, but consider this. You go in the bathroom and turn on a faucet at the lavatory. The hot water must then travel from the water heater to the manifold and through a dedicated line to your lav, then you step to the shower and wait again as the hot water leaves the tank, travels to the manifold then up the dedicated line to your shower, and if you happen to have two lavatories and the wife turns the water on at her lav once again you wait for the water to travel from the water heater to the manifold, then through a dedicated line to her lav. If we were to realistically compute all those losses in most instances the end result would be nearly the same, if not less in a main and branch layout. On the other hand, there is absolutely nothing in the code that would prevent us from installing a manifold and home run system with copper. If reducing water consumption is the main concern, then the best method would be to install a Main & Branch recirculating system, which provides nearly instantaneous hot water at the fixture. Taking this to the next level, if your desire to conserve water is based upon environmental concerns then here again a recirculating system wastes much less water however, if your concerns on saving water is based upon savings on the water bill, it is highly unlikely that either system will have any major effect because even though most municipal water suppliers do measure the exact number of cubic feet of consumption, generally they bill in blocks of 100cu.ft. One hundred cubic feet of water is approximately 600gallons and it is highly unlikely that you would waste 600gal in a month even with a long lead time to the fixtures.(Typically a 3br residential structure will average 300gal per day total consumption.) Many will argue that PEX is cheaper than copper, but here again, that is not always true. If we install PEX in a main and branch layout then PEX defintely has the price advantage but if we install a PEX manifold and home run system we must then install a both a hot and cold dedicated line to all lavatories and the shower plus and additional dedicated cold water line to the water closet. Thus at a minimum we have 5 lines from the manifold to the bathroom whereas with a main and branch we only have i hot and 1 cold line from the main to the bathroom. Now when you consider that one PEX fixture stubout will cost nearly as much as a bag of 20 copper elbows in the end the material cost for a PEX manifold system is almost the same as a copper system. In can be argued that the labor cost to install PEX is much less, but here again, this is not true. While it is much easier to run the PEX tubing, if the PEX is properly installed per code and manufacturers requirements PEX can ultimately involve more labor time, by example, the manufacturers installation specs state that PEX must be protected from UV light, both direct and indirect. Technically speaking, if you run PEX through an open stud bay in a basement, and if that basement has windows the you are required to cover the underside of that stud bay with a light proof material. When the manifold is wall mounted it must either be in a windowless utility room, enclosed in a cabinet or provided with a light proof membrane curtain. Copper requires an hanger within one foot of every major change of direction and one hanger for every 48". PEX is required a hanger for every 38" and the hangers must allow movement of the tubing. In addition, all PEX runs must have an additional 10% overall length to allow for expansion and contraction. (Now ask yourself, when was the last time you saw a PEX installation that was done by the book? In my jurisdiction we have a plumbing inspector who is hell bent on insuring all PEX is by the book, in fact, he brags that he has yet to see a PEX installation that would pass on first inspection.) For re-work PEX has the distinct advantage that it can easily be fished through walls, but then, the same can be done with roll copper. For new construction if PEX is run in a main and branch configuration like copper the overall cost advantage certainly goes to PEX but when we consider how much more tubing is used in a manifold and home run system most plumbers will offer a PEX maifold system or a copper main and branch system for the same price. Now in regards to angle stops at the fixtures. The codes require that all fixtures with the exception of tubs & showers must have an individual shutoff valve, which in most instances is the angle stop, however with the advent of the manifold system the valve on the manifold meets the requirement in most jurisdictions. On the other hand, some jurisdictions such as mine have ruled that the manifold valve is a Zone valve, and they still require the individual angle stops at the fixture. IMHO i would not have a fixture that does not have angle stops. Consider this, you have a minor drip from the lavatory faucet. If you have an angle stop you can easily reach under the sink and turn the water off, make the repair, then easily turn the water on again. On the other hand, if you have a manifold and no angle stop you must go to the manifold to turn the water off, and with my luck, your in an upstairs bath and the manifold is in the basement, no doubt at the opposite end of the house, so you go down two flights of stairs across the house and probably have to move bicycles, lawnmowers and who knows what to get to the manifold, then up two flights of stairs to make a simple repair, followed by another trip down the stairs to turn the water on, back up to check your work and pick up your tools. Personally I am getting too old to be running up and down the stairs all day, oh, but it does have its compensation because I am billing additional labor time for all those stairs..LOL. It is also argued that PEX will tolerate freezing and thawing without bursting a pipe, which is truc, but on the other hand what they don't tell you is that rodents of all varieties, mice, rats, rabbits, and opossums seem to have a sweet tooth for PEX. In fact, in the last five year we have made more service calls to repair rodent damage to PEX than to repair frozen copper lines.
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Them Europeans do have some good ideas as PEX (& masonry heaters, etc.) has been in wide use there long before here. However, their bonding at the fixtures appears to be overkill. The only grounding rqmt for single-family residences, in the U.S., is at the point of entry to the house. Any charge in the water system would be shunted to ground at that point and the circuit breaker should cut-off the electrical source. Of course, neither method protects completely if you are in the bath/shower and a non-GFCI electrical applicance falls in. As part of the Pentagon's renovation I observed the installation of the new copper piping and never saw grounds beyond primary supply points on each floor/wing. So apparently even commercial codes don't require bonding at the fixtures. Wonder why Europe requires it.
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PEX, done properly with a manifold and home run system, won’t be hugely cheaper than copper. But it will be 10x better in service and flexibility. Copper in slabs around here has about a 15 year lifespan because of the pinhole leaks.
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lazypup
16 years ago
The PEX crimping Tools work look very similar to a 24" bolt cutter and they work in a similar manner. The fitting and lockring is put on the tubing, then the jaws of the tool are placed over the lockring and the handles compressed in the same manner as cutting a bolt with bolt cutters. They can be very challenging to work in a tight spot however in most cases the tubing can be pulled out to an accessible place, the fitting made up, then the tubing is reinserted into the desired location.

You must also have a PEX "Go No-go" gage and each joint must be checked with the gage to insure it was crimped correctly.

You can download the complete PPFA (Plumbing Pipe Fitting Association) PEX installation handbook in PDF format from the following website:

http://toolbase.org/PDF/DesignGuides/PEX_Installation_Handbook_2006.pdf
dickross
16 years ago
I have replaced a couple pieces of pipe with PEX and have thought about replacing therest of it. The copper stubouts have me baffled. Why is it nobody makes a brass stubout?

I have thought about making my own. an elbow 1/2 PEX x 1/2 MNPT and a 1 or 2" brass nipple. a sheetmetal bracket would be brazed or clamped to this to allow inserting the pex end into the wall and then screwing the bracket thru the sheetrock into the stud. This could get expensive, I have 4 sinks (2 each) and 3 toilets (1 each) 11 total.

The outside faucets would be another issue. how do you mount one onto a brick wall?
donmorgen
Original Author
16 years ago
Hello Again:

Do I need an unroller, or is there a technique that I can use to properly "unroll" the tubing??

Thanks,

Don
shadow700
16 years ago
No, you don't need an unroller.

On the other hand, don't expect that you can just throw a roll of PEX on the ground and pull one end completely through your house - it can get tangled.

Depending on the length of the room I was working in and the length of the run, I would unwind about 10 to 15 feet at a time and pull that through, then unwind a little more, etc.

If you have another person helping you, then they can just feed it as you pull.
lazypup
16 years ago
You must exercise care when pulling the pipe, especially when pulling around a 90deg bend because you the pipe can kink. When making a 90 deg turn it is best to pull the tubing to the corner, then pull the next section rather than trying to pull the tubing around a hard bend.
donmorgen
Original Author
16 years ago
Lazypup:

Are you saying in regards to a 90 degree turn that I should cut the tube and use a 90 degree fitting?

thanks
Don
lazypup
16 years ago
no..no do not cut the tubing but you must be careful when pulling the tubing around a corner to insure it does not kink.

There is also a minimum radius allowance for bends in the tubing. There is a chart in that installation handbook that defines the bend radius
donmorgen
Original Author
16 years ago
Lazypup:

OK I think I get it. e.g If I'm running the tube in my basement along or through joists I can carefully run it directly from the coiled tubing, but when I go through the floor making a 90 degree turn I should first gather some extra tubing at the last joist before I carefully pass it upstairs?

Don
donmorgen
Original Author
16 years ago
Manifold Question:

Can I gang together two manifolds of the same size copper pipe (using a large diameter say 1-2 inches would be better?)that would have different sized pex terminals i.e. mostly 1/2" but at least one with 3/4"?

This is the type of manifold that I would sweat two together but they would have different sized terminals:

http://www.pexsupply.com/categories.asp?cID=519&brandid=

Would this cause any problems?

Thanks
Don
lazypup
16 years ago
When running a manifold system all the lines are sized much different than when running a main and branch layout..

That it why most jurisdictions require the installer to be trained in the proper installation of PEX.. At a minimum,,download the installation manual and follow it in detail otherwise your going to end up with a big mess.
donmorgen
Original Author
16 years ago
I have downloaded the manual, and I don't see where my questions are addressed. If I missed something, please tell me what page it's on.

Thanks,
Don
lazypup
16 years ago
In the "INSTALLATION HANDBOOK: CROSS LINKED POLYETHYLENE (PEX) -HOT AND COLD-WATER DISTRIBUTION SYSTEMS.

Tubing bending radius......................pg 6
Manifold sizing table..................... PG 9
Fixture Line sizing........................PG 10
donmorgen
Original Author
16 years ago
Lazypup:

I thought the table on page #9 was referring to the diameter of the manifold needed for a certain level of maximum demand (velocity) of the water.

I wanted to know two things. Is a larger diameter manifold than required ever a bad thing? Secondly, can I mix the output terminals with both 3/4 inch and 1/2 inch nipples?

Thanks
Don
lazypup
16 years ago
If you are running a PEX manifold system I fail to see where you will be using 3/4"?

Standard fixture runs are 3/8" & 1/2"

The size and number of the output nipples is determined by the MFG specifications for the manifold and the main line in the manifold is designed by the manufacturer to supply full volume and pressure for the max number and size of taps on the manifold.

There would be no advantage in oversizing however, if you connect two manifolds in series on a common feed that effective reduces the feed to each manifold by 1/2 and should not be done.
donmorgen
Original Author
16 years ago
Hi:

Here's why I need two(one hot & one cold) 3/4" terminals:

My current game plan is to modify my current copper plumbing with PEX. I have a two story home with an exposed basement ceiling. I can clearly see where the Â½" copper pipes branch off the Â¾" main to the separate sites of the kitchen and Â½ bath above on the first floor. I am considering disconnecting and sealing off the current Â½" pipes that feed to the kitchen and re plumb PEX from a manifold to each fixture using the same holes through the floor above. The Â¾" copper would then be connected as a separate line in the manifold as well to continue to supply water to the second floor.

The reason IÂm not thinking of redoing the 2nd floor plumbing immediately is because it presents some major obstacles for my limited plumbing and carpentry skills. The current pipes are hidden in the walls and ceilings, and I donÂt know exactly where they are.( Ideally if I knew where they were I could cut them out and replace them with PEX tubing, fishing them through the same holes in the walls and joists.) Instead IÂm considering a new route maybe through closets etc. to reach the upstairs fixtures.

Don
lazypup
16 years ago
I fully understand what you are attempting to create. It is called a hybrid system where you will continue to use the main and branch layout for part of the structure and a PEX homerun system for another part. The point I am trying to make to you is that there is no reason to connect the 3/4" branch lines to the manifold. If you want a shutoff valve on those lines simply install a ball valve as a zone shutoff and use the manifold to feed the new individual fixture lines.
donmorgen
Original Author
16 years ago
I need one water source to supply two different lines (copper & Pex), and I was thinking of using the manifold to accomplish this split. Is there a better way?

Don
lazypup
16 years ago
A manifold is nothing more than a group of two or more branch connectors with or without valves built on a common body. The exact same thing can be done by installing a Tee on the existing main line.

If you insist on getting a manifold large enough to support 3/4" lines you will need to move up to a commercial manifold rather than a residential one, which would dramatically increase the cost. For a fraction of the difference you could install tee's.
fayemarie
15 years ago
I am currently using pex to plumb my new construction home , I am using 1
main manifold and 2 remaote manifolds . The main supply lines that run from
one manifold to the next is 3/4 " . I am using 1/2 " for the fixtures and 3/8"
for the toilets and icemaker . I ordered my materials from Mountainview
Supply and they were extremely helpful with all my ordering and questions .
I also found their prices to be very competitive .

Need Help Pex Plumbing

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