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  1. #1
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    Default CPVC fitting labeled "cold water only"

    While inspecting a hot water tank today I noticed that the cpvc fitting connected to the tpr valve said "cold water only". I thought cpvc was designed for hot and cold water.

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    Default Re: CPVC fitting labeled "cold water only"

    There are several brands of plastic TPR pipe on the market, the more prevalent is polyethylene, a white-ish plastic pipe made for TPR valves.
    Are you sure it was CPVC?

    Dom.


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    Default Re: CPVC fitting labeled "cold water only"

    It was the cream colored pipe or off white pipe. The fitting was connected to a labeled cpvc pipe. The pipe and the fitting were the same color.

    Greg Jenkins

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    Default Re: CPVC fitting labeled "cold water only"

    I have never seen a CPVC pipe or fitting that read "cold water only".

    Was this a sticker, a label, a notice, etc.? Where did this wording occur? Have any photos?

    Dom.


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    Default Re: CPVC fitting labeled "cold water only"

    Regardless what it was made from, it if was labeled "cold water only", then, no, it is not allowed for use as a T&P relief valve discharge pipe.

    Jerry Peck
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    Default Re: CPVC fitting labeled "cold water only"

    I did not take a picture of it. The wording was embossed into the plastic. It was not an affixed label.

    Greg Jenkins

  7. #7
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    Default Re: CPVC fitting labeled "cold water only"

    Well I'll be derned. Just did a little research -- apparently ALL CPVC MIP'S are NOT recommended for transitioning from metal to cpvc. Differences in thermal expansion between the metal and CPVC may cause leaks.

    Here's but one example:

    http://www.ppfahome.org/images/CPVC_...tion_FINAL.pps


    (scroll down a bit.)

    Even though the MIP's say for cold water only, I wonder if it matters if it's a situation where you're just going from a CPVC FIP to MIP.


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    Default Re: CPVC fitting labeled "cold water only"

    Greg,

    Ask and thou shall receive.. Is this board not the greatest?

    I have been back tracking my files for the last month and probably found exactly what you are talking of. I found the same CPVC last month on a TPR valve.

    Does this look familar?

    Rick

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    Default Re: CPVC fitting labeled "cold water only"

    Rick - That's the fitting.
    The house I was inspecting was new construction and I had another reason to speak with the builder this morning. I told him about the fitting and he said it would be corrected. He too was not familiar with the "Cold Water Only Marking".
    Thanks for all the input. That's what I like about this board.

    Greg Jenkins

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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Joshua Hardesty View Post
    Well I'll be derned. Just did a little research -- apparently ALL CPVC MIP'S are NOT recommended for transitioning from metal to cpvc. Differences in thermal expansion between the metal and CPVC may cause leaks.

    Here's but one example:

    http://www.ppfahome.org/images/CPVC_...tion_FINAL.pps
    I'll be derned too!

    Even though the MIP's say for cold water only, I wonder if it matters if it's a situation where you're just going from a CPVC FIP to MIP.
    I'll say yes if you are talking about changing from CPVC to another material (metal), but not if you are going CPVC to CPVC (but why would you do that?).

    Jerry Peck
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  11. #11
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    Default Re: CPVC fitting labeled "cold water only"

    Eh, knows Jerry. I can't think of a situation off the top of my head where I'd need to transition from CPVC-FIP to CPVC-MIP, unless I ran out of couplings. heh. The literature says not to be used as a transition from CPVC to metal, so that doesn't exclude cpvc-cpvc (which isn't much of a transition :/ ), but the fitting itself only says COLD WATER ONLY.


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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Joshua Hardesty View Post
    Eh, knows Jerry. I can't think of a situation off the top of my head where I'd need to transition from CPVC-FIP to CPVC-MIP, unless I ran out of couplings. heh. The literature says not to be used as a transition from CPVC to metal, so that doesn't exclude cpvc-cpvc (which isn't much of a transition :/ ), but the fitting itself only says COLD WATER ONLY.

    Joshua,

    "so that doesn't exclude cpvc-cpvc (which isn't much of a transition :/ ), "

    Then that fitting would not be a "transition", it would just be an "adapter".

    "Adapters" do not have that limitation as they are used for like material to like material, thus the expansion and contraction coefficients would be the same.

    Now, the key is, when we see an 'adapter' being used as a 'transistion', we need to know (to remember) to look and make sure it is marked 'Cold water use only', otherwise they are using an "adapter" instead of a "transition" fitting.

    Likewise, we need to remember to look at 'adapters' being used as 'adaptors' to make sure they are not "transistions" and are not marked 'Cold water use only'.

    In reality, I'm guessing that almost every 'adapter' we see being used is really being used as a "transitionadapterstransitionstransition", which means it is incorrect.

    Recently I re-worked my sprinkler system, removing the interior of the indexing zone valve to allow it to serve as a manifold instead of a valve, then installed electrically controlled valves for each zone off the manifold. I used "adapters" as "adapters" from the PVC pipe into the PVC valves, so I actually did it correctly, without knowing that I was. Whew!

    Jerry Peck
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  13. #13
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    Default Re: CPVC fitting labeled "cold water only"

    So where would you be able to use a CPVC male adapter since they are most always used to change from metal to CPVC pipe?


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    Default Re: CPVC fitting labeled "cold water only"

    I was re-reading these posts and checked out the links posted and read the documentation. It seems to me that all of the documentation is referring to the water supply system that is under pressure. It makes sense that leaks may occur if the system is under pressure. But what is the problem with using the cpvc fitting labeled "cold water only" on the TPR valve. The cpvc is still rated for hot water and the system is not under pressure so leaks are not an issue. I found the same fitting on another water tank today. The home was a manufactured home. I suspect there are a gazillion of these things attached to water tanks and probably no problems.

    Greg Jenkins

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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by James Duffin View Post
    So where would you be able to use a CPVC male adapter since they are most always used to change from metal to CPVC pipe?
    James,

    Basically going from CPVC pipe to a valve or fitting which is threaded instead of slip for solvent welding.

    Jerry Peck
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    Default Re: CPVC fitting labeled "cold water only"

    Greg,

    The problem is that those are made for (molded right into the fitting) "Cold Water Only" and the T&P relief valve is "hot water".

    Therein it is wrong.

    Why try to justify something which is "wrong". If the speed limit is 65 mph and everyone is going 85 mph, will you try to talk your way out of getting a ticket by saying "What is wrong with me going 85 mph - everyone is doing it?", just because 'it is always done' does not make it correctly done.

    That's what we are for, and why there will always be a need for us - because people do things the way they've always done it ... right or wrong.

    Just like people who drive 85 mph all the time ... "Well, it has not been a problem ... yet."

    Jerry Peck
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  17. #17
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    Default Re: CPVC fitting labeled "cold water only"

    Jerry,

    I know technically it is incorrect and I am not trying to justify it so I can overlook it when I am inspecting. My point is that I think there are many examples where we all use things that they were not desinged for. Manufactures of products can not test there products for every possible crazy way that we humans might try to use it. (how many times have you used your screw driver to pry something? - well it was designed to turn a screw.)
    Now that I know to look for the wording on the fitting, I will continue to call it out because technically it is wrong.
    In the words of Forest Gump "That's all I have to say about that."

    Greg Jenkins

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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Jerry Peck View Post
    Why try to justify something which is "wrong".
    Quote Originally Posted by Greg Jenkins View Post
    My point is that I think there are many examples where we all use things that they were not desinged for. Manufactures of products can not test there products for every possible crazy way that we humans might try to use it.

    Greg,

    I was trying to head the above off before it got there.

    When things are labeled "Cold Water Only", there is a reason for it, in this case, it has been tested for it, and it failed, the reason being posted in that information.

    Just this afternoon I assembled a tricycle for our granddaughter, I used the handle of a screw driver for a hammer to try to hammer the axle caps on, when that did not work, I went and got a hammer (I have many from my construction days). Do you want your clients to have to go get something, or advise them it's not right in the first place?

    Like you and Joshua, I just learned about those things yesterday too.

    Crimeny, how many things are we going to have to keep learning about?

    Jerry Peck
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  19. #19
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    Default Re: CPVC fitting labeled "cold water only"

    While the cold water only marking surprised me I understand why it's there. The threaded portion of the transition fitting is not suitable under pressure and temperature conditions combined.

    I don't think there is a real problem with using it for the TPR discharge as the CPVC is approved for that use and you have to use a transition fitting of this type to be able to use the CPVC pipe which is not under high pressure(not closed system) when called upon to discharge the water. JMHO


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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Michael Larson View Post
    While the cold water only marking surprised me I understand why it's there. The threaded portion of the transition fitting is not suitable under pressure and temperature conditions combined.
    Michael,

    That's not the reason given for them not being suitable for that use.

    I don't think there is a real problem with using it for the TPR discharge as the CPVC is approved for that use and you have to use a transition fitting of this type to be able to use the CPVC pipe which is not under high pressure(not closed system) when called upon to discharge the water. JMHO
    That's not what was being stated. What we all have been seeing are "adapters", not "transitions".

    In the slide show Joshua linked to, "transitions" are shown on slide 10 (which I have attached).

    When connecting CPVC to metal, a "transition" is required, not an "adapter".

    Attached Files Attached Files
    Jerry Peck
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  21. #21
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    Default Re: CPVC fitting labeled "cold water only"

    Jerry,

    I am essentially agreeing with Greg in post 14.

    I'd have a hard time calling this out as a problem in need of resolution. JMHO

    There is little danger in this case. Do you see one?

    Though it is wrong, I have seen similar(not marked cold only) fittings screwed into the top of a water heater tanks and yes I called it out.


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    Default Re: CPVC fitting labeled "cold water only"

    Michael,

    "I'd have a hard time calling this out as a problem in need of resolution."

    I would not have any problems writing it up.

    "If it is not right, it is wrong."

    I write up what is "not right".

    I let the client decide what they want to address. Without me writing it up, they cannot address it.

    Jerry Peck
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  23. #23
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    Default Re: CPVC fitting labeled "cold water only"

    It's a judgment call. We simply have different opinions.


  24. #24
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    Default Re: CPVC fitting labeled "cold water only"

    Just remember not all CPVC fittings say for cold water only. I have one on my desk as I type that meets the nsf standards for hot water use, and it looks exactly like the one in your photo. Granted I don't know how old it is, but at one time, in the past, it was approved. I would be careful how you write it up. I also agree with using the brass/CPVC fittings.

    Thanks for the Thread, I will bring this up at all of our meetings


  25. #25
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    Default Re: CPVC fitting labeled "cold water only"

    All-CPVC male adapters are not meant to transition from metal to CPVC. Why wouldn't you call that out?

    They make brass-CPVC male adapters to address this issue.


    Short-bend 90's are not meant to transition from vertical to horizontal. Yet, it would most likely work.

    Would you not call that out, just because it'd probably work fine?


    Let's say the TPR is routed from the heater in the attic to the outside without draining into the catch pan or an air gap in the attic. They owners go on vacation, the TPR blows off, there would probably be enough pressure in that pipe to find any leaks. Over the course of a week or two, those leaks drip onto the floor of the attic and cause damage. (Just because a hose is open at both ends doesn't mean it can't leak if one side isn't screwed onto the hose bibb tightly enough.)


    I'm sure the warning was more intended from something like screwing a CPVC male adapter into a brass valve where it would stay under pressure all the time, but since the water coming out of a TPR valve is quite a bit hotter than the water normally found inside the pipes, the leaks would probably be worse.


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    Default Re: CPVC fitting labeled "cold water only"

    I stopped by one of the Big Box stores today and looked at the PVC 'adapters', *all of them* were listed as "adapters", *none of them* were listed as "transitions".

    "Adapters" "adapt" from slip (solvent cement welded) to threaded.

    "Transitions" "transition" from one material to another material.

    I then went and looked at all of the CPVC 'adapters', and they too were all listed as "adapters", and all of them also had "cold water use only" on them.

    The "cold water use only" was in very small lettering and at first glance looked like some listing information, such as NSF, etc., but, upon close examination, they all said "cold water use only".

    Jerry Peck
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  27. #27
    Tony Watson's Avatar
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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Jerry Peck View Post
    "Adapters" "adapt" from slip (solvent cement welded) to threaded.

    "Transitions" "transition" from one material to another material.
    To threaded what, if not another material?


  28. #28
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    Default Re: CPVC fitting labeled "cold water only"

    From the fifth slide of the paper I linked:

    "Male threads, such as those found on a CPVC male adapter, can be used as a transition but only on the cold water portion of the system."


  29. #29
    Tony Watson's Avatar
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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Joshua Hardesty View Post
    From the fifth slide of the paper I linked:

    "Male threads, such as those found on a CPVC male adapter, can be used as a transition but only on the cold water portion of the system."
    Good answer!!!


  30. #30
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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Tony Watson View Post
    To threaded what, if not another material?
    Tony,

    From one of my posts above:

    Quote Originally Posted by Jerry Peck View Post
    James,

    Basically going from CPVC pipe to a valve or fitting which is threaded instead of slip for solvent welding.
    There are many uses for CPVC "adapters" in hot water systems.

    There are also many uses for CPVC "transitions" in hot water systems.

    Yet, to my knowledge, I have never seen a CPVC "transition" used in a hot water system to transition from CPVC to metal or other material ... all I have ever seen are "adapters" used for that purpose (and, until the other day above, I was not even aware of that difference).

    Yes, a CPVC "adapter" may be used as a "transition" fitting on a cold water system, however, that does not make it a "transition" fitting - it is still and "adapter" fitting, it is 'just being used as a transition fitting'.

    Jerry Peck
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  31. #31
    Tony Watson's Avatar
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    Default Re: CPVC fitting labeled "cold water only"

    What a defination of " is "

    You are right, I concede the point. A transition fitting is an adaptor, but an adaptor is not necesarly a transition fitting.
    ( but an adaptor can be used on the cold side for something)


  32. #32
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    Default Re: CPVC fitting labeled "cold water only"

    What I'm curious to know is, if the coefficient of thermal expansion is different enough between metal and CPVC as to possibly loosen the connection enough to cause a leak when using male CPVC threads, will the greater expansion of the metal when using a female CPVC adapter cause excessive stress to be put on the connection causing early failure of the cpvc?


  33. #33
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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Joshua Hardesty View Post
    will the greater expansion of the metal
    Plastic has the greater thermal expansion.

    when using a female CPVC adapter cause excessive stress to be put on the connection causing early failure of the cpvc?
    I believe their point was that the difference in expansion between the two materials will cause the threads to no longer meet and seal, leading to leaking.

    By that, I also question whether the difference in expansion between the two materials will weaken the CPVC threads.

    Same direction you were heading, just more confined (to the improperly used CPVC adapter threads).

    I would suspect that if you had some piping which was CPVC-then metal-then more CPVC, that the overall expansion of that combined piping would be less than if the entire length were CPVC (because plastic has a greater coefficient of expansion than metal does - basing this on electrical PVC versus electrical metal conduits).

    Jerry Peck
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  34. #34
    Joshua Hardesty's Avatar
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    Default Re: CPVC fitting labeled "cold water only"

    That seems counterintuitive to me.

    Male threads, which fit inside of metal, will expand more than said metal and cause a leak? But, Female threads, fitting over the metal, will expand more and it's not a problem? Seems like the male threads expanding would cause a more snug fit, while the female threads would cause a more loose fit. Oh well, that's why I'm not a scientist.


  35. #35
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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Joshua Hardesty View Post
    That seems counterintuitive to me.

    Male threads, which fit inside of metal, will expand more than said metal and cause a leak? But, Female threads, fitting over the metal, will expand more and it's not a problem?
    Joshua,

    I believe if you go back and review those links you posted you will find that "adapters" include both male adapters and female adapters, and that "transitions" include both male transitions and female transitions.

    Makes your science easier, I believe.

    Jerry Peck
    Construction/Litigation/Code Consultant - Retired
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  36. #36
    Joshua Hardesty's Avatar
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    Default Re: CPVC fitting labeled "cold water only"

    Ahh I see, it's a bit of tricky wording in my brain.

    "Male threads, such as those found on a CPVC male adapter, can be used as a transition...(blahblah)

    I took that to mean only CPVC male threads, but I suppose it could also mean copper or brass male threads as well. They don't specifically mention a female adapter being prohibited, but then give the example of the CPVC socket x female thread with the gasket being considered a transition and not an adapter.


  37. #37
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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Joshua Hardesty View Post
    They don't specifically mention a female adapter being prohibited,
    Male adapter threads screw into ... female adapter threads.

    Jerry Peck
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  38. #38
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    Default Re: CPVC fitting labeled "cold water only"

    Glad to see you found the presentation on the PPFA website. The key is that thermo-cycling (going from hot to cold many times) will impact the interference type male threads on an all CPVC “adapter” in a metal fitting system. Since the threads in such a fitting make the physical seal, this may cause a leak to form on a line that will originally appear just fine.

    This is because the metal side of the threads will not expand, nor contract, in the same way as the CPVC side.

    An all CPVC “transition” fitting therefore, seals not on the threads, but on an elastomeric gasket instead. The presentation goes into more detail, and there are other types of transition fittings available.

    For the presentation and other CPVC related documents: http://www.ppfahome.org/cpvc/pubscpvc.html

    Mike
    PPFA


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    Default Re: CPVC fitting labeled "cold water only"

    Quote Originally Posted by Mike Cudahy View Post
    Glad to see you found the presentation on the PPFA website.

    For the presentation and other CPVC related documents: http://www.ppfahome.org/cpvc/pubscpvc.html

    Mike
    PPFA
    Mike,

    Thank you for that link.

    All of us should read and download this, the PPFA Installation Handbook: CPVC Hot & Cold Water Piping: http://www.ppfahome.org/pdf/PPFA_CPV...anual_2006.pdf

    For those who see CPVC and gas water heaters, be sure to read the "Water Heater Connections" section on page 6: "gas water heaters there should be at least 6 inches of clearance between the exhaust flue and any CPVC piping (photo K). Twelve-inch long metal nipples or appliance connectors should be connected directly to the heater so that the CPVC tubing cannot be damaged by the build-up of excessive radiant heat from the flue."

    Jerry Peck
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  40. #40
    Mike Cudahy's Avatar
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    Default Re: CPVC fitting labeled "cold water only"

    And pay attention to local codes....

    In Western UPC states, they may require an 18" length of metallic tubing from all heaters - gas or electric, before PEX or other plastic materials.

    "PEX shall not be installed within the first eighteen (18) inches (457 mm) of piping connected to a water heater." - UPC language



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