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Discussion Starter #1
About 2 1/2 years ago my company re piped about 200 ft of heating water supply and return underground with 6'' CPVC. We have had nothing but problems out of it. We have made numerous repairs of couplings and 45's It got so bad that we replaced the whole run, again it leaked. The glue joints are breaking. Had it tested by the glue company and by the manufacturer. They both blame each other. I am beginning to believe its something in the ground reacting with the chemical and the glue. Some of the fittings have blown completely off after months of being in service. Needless to say we are at our wits end and no one has any answers. I voted that we tear it all out and go back with steel, which is what they had in the first place. Electrolysis reeked havoc on the steel before. That's why they chose CPVC. Anyone ever ran into this?
 

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Discussion Starter #2
Think I answerd my own question....

No allowance for expansion- CPVC has a greater thermal coefficient of expansion than other materials a plumber has traditionally used. In other words, it will expand more when used in a hot water application than other materials, such as copper. If this characteristic is not considered in the design and installation, disastrous results can ensue. CPVC expands 4.7 inches per 100 feet for every 100 degree Fahrenheit rise in temperature. In a multi-story building where long runs of piping are common, it is especially important to allow for this expansion. Every straight run of pipe must be provided with a properly sized and supported expansion loop. The expansion loop will absorb the deflection resulting from thermal expansion of the pipe. In the absence of the expansion loop, the expansion of the pipe will stress the fittings to the point of failure.
 

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Discussion Starter #4
I didnt know that CPVC expanded at 5 in per 100 ft for every 100 degree rise. The run is well over 200 ft. This has to be the problem. They are running their heating water at about 130 to 135 degress. The hottest they run is 140.
 

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Regular PVC has similar results, poly vinyl chloride in states like Illinois is a self destructing sytem because of the temperature changes, this was revealed ten years after the product came into general use, but by then it was too late, and companies worked on coming up with ways to compensate for the product defect, like using mechanical expansion joints.
 

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Discussion Starter #6
What about glycol chemicals, I just read that they dont react too well with the glue.
 

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What about glycol chemicals, I just read that they dont react too well with the glue.
The glycol systems I have worked on were done with very heavy schedule CPVC that we threaded and put together just like galvanized steel pipe, but that was many years ago.
 

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Discussion Starter #8
This is Sch 80 CPVC. Everything I have read up on suggest that expansion loops are a must. And glycol based chemicals reek havoc on the glue joints. There ARE NOT any expansion loops in this system which is underground and they run glycol through their system
 

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You might want to compare replacing it with CPVC done correctly with threaded fittings against doing it in stainless steel with victaulic joints and stainless fittings, or even stainless steel with welded fittings.
 

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This has been on going for 2 yrs and they finally put me on it, now I have to clean up this mess.
 

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Isn't that even more incentive to fix it right on the first try?
Yeah it is, I wasent saying it was a bad thing. I just want to make sure that is exactly the problem before I bring my cards to the table. I feel pretty sure that is what is going on.
 

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As a side note:
Beveling the ends of the pipe are very important also. If your not already doing it. This prevents the sharp edge of the pipe pushing the glue out of the fitting.
 

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Discussion Starter #15
We are installing expansion joints which should have been installed upon burial. This seems like a step forward.
 

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Discussion Starter #16
I agree with KTS. Tell them to shell out the dough to go stainless. Get soil tested first to see if there is anyhing in it that will attack it.
They did shell out the dough, a bunch of it. Now its on us....
 

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Regular PVC has similar results, poly vinyl chloride in states like Illinois is a self destructing sytem because of the temperature changes, this was revealed ten years after the product came into general use, but by then it was too late, and companies worked on coming up with ways to compensate for the product defect, like using mechanical expansion joints.

Hot water is not allowed in or rated for PVC??:blink:
 

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Discussion Starter #18
It still expands and contracts.... KTS was pointing out that CPVC expands but PVC does as well
 

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I've installed expansion joints for all kinds of DHW systems and a few process systems. Used PVC for water services even, but I've never put an exp. jt. in on the PVC. Do I start to sweat this or what. I'm thinking not due to the avg. water temp. of the gnd water hear @ 77 F.
 

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Discussion Starter #20
I've installed expansion joints for all kinds of DHW systems and a few process systems. Used PVC for water services even, but I've never put an exp. jt. in on the PVC. Do I start to sweat this or what. I'm thinking not due to the avg. water temp. of the gnd water hear @ 77 F.
Down here we don't either, our average is about the same as yours. He was talking about Illinois so I am not sure bout that one
 
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