I have a shop located in the old garage / machine shop of a factory that is now out of business. I am at the mercy of the original plumbing of the entire factory which covers a huge area that is fed by a two inch main and I am at the end of the run. Every winter I face the challenge of the majority of the factory not being heated and if the winter is cold enough, pipes freeze and when it thaws flood the shop. My plan is to shorten the run by breaking the line at the shut off, reducing to 3/4, and running pex for about 200 feet with a line of heat “tape” and covering it with foam insulation. I understand the shrink and expansion issues and plan to hang the tubing per specs as far as slack and movement allowances are concerned. Where there needs to be a loop, I can put a box made from building foam to cover the loop. No portion of the pex would be exposed to sunlight since it would all be covered with foam. Once I get near the water use areas, I plan to adapt to copper and redo all of the existing plumbing in a more “normal” manner. Code really isn’t an issue with my location, but durability and bang for the buck is. I have a number of questions. Are there any issues with the “heat tape” and pex contact? Do I need any sort of regulator to ensure no problems with the two inch to 3/4 reduction and the possibility of blowing apart the initial connection? By using copper (again, 3/4) once I get to my first point of water use, can I forego the use of manifolds since the copper is basically serving as one? Finally, does this have more potential of solving my problems, or increasing them. I’m not afraid of minor failure with an enemy I know every inch of since I have dealt with major failure of a huge plumbing monster every winter for the past 10 years. Last year we had a break at the first turn in the 2 inch main and came in to water flowing out the front door of my office. It’s a matter of conditioning and insulating 200 feet (actually less than that, but it’s a good round number to work with) of pex or the over 1500 feet of existing pipe. I have no high use water needs, with only two bathrooms, one shower a water cooler and one slop sink in my part of the facility. There is also no possibility of the rest of this facility ever being used without extensive rebuilding and replumbing and that is a very very remote possibility. Any advice, encouragement that I’m on the right track, or even a condescending discussion of what a fool I am to try this would be greatly appreciated. As a side note, I can do without the simple solution of why don’t I relocate since I could never find the square footage I have now for 10 times what I am paying. Running copper all the way would work, but also for 10 times the expense. Thanks for any help you may be able to offer.
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Replies
I don't think you said where
I don't think you said where you live, but one good thing about pex is it has some flex so it can tolerate some freezing.
The pex will work with heat tape. One other option is poly pipe with the heat tape inside the pipe.
St. Louis region. Procrastinated after buying the materials and next week it will be in single digits for a few nights. My current set up handles a day of this or a few 15 degree days, but a week of it means trouble and I believe the pex, heat tape and insulation will withstand everything we get. The biggest concern to me is the step down from 2 inch to 3/4 and what that volume of water will do to the initial fitting. My first thought is a ball valve right after reducing and before the pex connection that I can pull the handle off of after regulating the pressure. On the other hand, if it isn't necessary and I'm just over thinking it, then I'd rather leave it out of the system.
zk:
You haven't said what the
zk:
You haven't said what the water pressure is at your 2" take-off point or how many of your fixtures could be in simultaneous use.
But assuming 45-60 psi you would be able to shower and flush 1 toilet concurrently, but no more than that. If you are the only user that restriction may not be a problem.
The stepdown shouldn't be a problem - water volume will be gated in normal use by the size of the 200' line. You want maximum pressure to your pex line.
You can plumb conventionally with copper at the end of your pex run - no need for manifolds.
Do put a valve in at each end of the run for your convenience in maintenance.
Regards,
Jim Jim Jim
I'm not certain of the
I'm not certain of the pressure at the head end. My concern was the relationship between the water volume behind the step down and if all that water reduced to a 3/4 inch stream would create enough pressure to be a problem at the first pex fitting and perhaps blow it loose. Again, I would rather ask a dozen foolish questions and overthink this than to make any foolish mistakes by not asking. I have others working at the shop, but it is rare the shower is used and there are only three working toilets and one urinal. I don't anticipate lack of pressure to be a problem, but I did have some concern about the length of the run. I very much appreciate everyone's imput and in the end I was able to see my duh moment of debating about my own valve at the head end rather than being sensible and putting one at both ends. Probably would have ended up putting in both as I put it all together, but this discussion will save a trip to the big box at the end of the job to buy the second one. Thanks again.
Water does not work that way.
The pressure will not increase when the size is reduced. Statically the pressure will be exactly the same in all parts of the piping.
When you have water flow then there is dynamic pressure drop. The higher the flow rates, the longer the run, and the more the pressure drop.
Just like electricity.
You can have a 20 amp circuit and plug in a 18 gauge extension cord. And if you plug a 60 watt lamp into it no problem.
But if you try to run a CS on it you would have large voltage drop.
As for as the manifold goes there is no reason that you need one with PEX. Just that will PEX runs to the fixture the flexability of the installation makes that a practical option. And in some cases the centralized shutoffs on each run are very handy.
But you can also PEX full size and branch off at each fixture.
BTW, why are you running copper at the end and not all PEX.
I was bouncing back and forth from pressure should be equal to what if I'm wrong, and I should have done the reverse engineering of the old electricity is like water that I'm so familiar with to confirm. Thanks for the explanation. In the same vein, I'm finishing out with copper because it's something I am familiar with and old habits die hard. It wouldn't be a great leap for me to go ahead and finish with pex and I'm willing to be convinced. I was hesitant to use pex at all since it isn't rated for outdoor use and the first 150 feet of the location is not outdoors but might as well be temperature wise. After I determined the real issue to be ultraviolet rather than freezing I bought the materials to do it, got busy and put it off until a lull I knew I'd have after the 1st. Of course, the cold snap has come and I need to get it done in the next couple of days. That said, I'm probably already convince to finish it out in pex if only to actually win the battle a day before it begins. Thanks again.
I had a similar situation last winter in Portland, Maine. The only suggestion I have is that if the heat tape is designed for metal pipe, then it helps to put the temperature sensor into something metal. I wrapped the pex with the heat tape and foam insulation, and put the temperature sensor on a metal post. That kept everything from freezing. However, I bet it spun the electric meter at an alarming rate.
If you are just doing a few fittings, look at the Sharkbite fittings at Home Depot. They are expensive at about $5 a fitting (you use few with pex anyway) but they are so simple and foolproof and FAST you will find it easy money to part with.