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  • #31
    Re: Tankless flush

    Originally posted by OnceandforAll View Post
    As I stated earlier in the thread:
    Do any of the tankless manuals show diagrams & have instructions for a T&P requirement?

    Rinnai
    Takagi
    Noritz
    Rheem/Paloma

    Others?

    J.C.

    Comment


    • #32
      Re: Tankless flush

      Originally posted by JCsPlumbing View Post
      Do any of the tankless manuals show diagrams & have instructions for a T&P requirement?

      Rinnai
      Takagi
      Noritz
      Rheem/Paloma

      Others?

      J.C.
      Nope, all require PRV's rated for 150 psi and the btu rating equal to the max btu output of the unit......

      companies who manufacture the isolation kits (like the ones in the picture) all come with prv's.


      edit***

      If you call and ask anyone of the above listed companies....they will instruct you that local code takes
      precedent.
      Last edited by OnceandforAll; 03-07-2009, 08:18 PM.

      Comment


      • #33
        Re: Tankless flush

        This was taken from the Rinnai website:

        An approved pressure relief valve is required by the
        American National Standard (ANSI Z21.10.3) /
        Canadian Standard (CSA 4.3)
        for all water heating
        systems.
        The relief valve must comply with the standard for

        Relief Valves and Automatic Gas Shutoff Devices for
        Hot Water Supply Systems ANSI Z21.22
        and/or the
        standard
        Temperature, Pressure, Temperature and
        Pressure Relief Valves and Vacuum Relief Valves,
        CAN1-4.4
        .
        The relief valve must be rated up to 150 psi and to at
        least the maximum BTU/hr of the appliance.
        The discharge from the pressure relief valve should
        be piped to the ground or into a drain system to
        prevent exposure or possible burn hazards to
        humans or other plant or animal life. Follow local
        codes. Water discharged from the relief valve could
        cause severe burns instantly, scalds, or death.
        The pressure relief valve must be manually operated
        once a year to check for correct operation.
        The relief valve should be added to the hot water
        outlet line according to the manufacturers
        instructions. DO NOT place any other type valve or
        shut off device between the relief valve and the water
        heater.
        Do not plug the relief valve and do not install any
        reducing fittings or other restrictions in the relief line.
        The relief line should allow for complete drainage of
        the valve and the line.
        If a relief valve discharges periodically, this may be
        due to thermal expansion in a closed water supply
        system. Contact the water supplier or local plumbing
        inspector on how to correct this situation. Do not
        plug the relief valve.
        Neither Rinnai nor the
        American National Standard
        (ANSI Z21.10.3) / Canadian Standard (CSA 4.3)

        requires a combination temperature and pressure
        relief valve for this appliance. However local codes
        may require a combination temperature and pressure
        relief valve.

        Comment


        • #34
          Re: Tankless flush

          It's obviously open to interpretation by the authority having jurisdiction. When you consider that said authority may not know enough to properly interpret either the code or the manufacturer's installation instructions, a request for a T & P valve would not surprise. The fact that all the manufacturers of tankless water heater isolation valves ship them with pressure relief valves (and not T & P valves) speaks volumes, to me at least.
          Last edited by Plumbus; 03-08-2009, 12:12 PM.

          Comment


          • #35
            Re: Tankless flush

            If you install the tankless with a service kit, where do you suspect the probe for the temp part of the relief valve is going to go?

            YOU DO NOT INSTALL A T&P WITH A TANKLESS UNIT, T&P VALVES ARE ONLY FOR STORAGE TYPE WATER HEATERS
            sigpic

            Robert

            Comment


            • #36
              Re: Tankless flush

              Originally posted by westcoastplumber View Post
              If you install the tankless with a service kit, where do you suspect the probe for the temp part of the relief valve is going to go?

              YOU DO NOT INSTALL A T&P WITH A TANKLESS UNIT, T&P VALVES ARE ONLY FOR STORAGE TYPE WATER HEATERS
              I just realized what you mean about this and you are right!

              I always buy the connection kit with the isolation valves and the PV in the box there is no room for the temp probe... I need to pay better attention sometimes.
              Last edited by OkieBill; 03-10-2009, 08:37 AM. Reason: not a PRV just a PV...DOH

              Comment


              • #37
                Re: Tankless flush

                By PRV i meant Pressure Reducing Valve. In my area every home has one. City pressures are over 100psi just about everywhere and as much as 180psi in some places.

                As far as the t&p - yes i understand what JC is saying however it is not what the code says. The manufacturers of the drain kits also make a model w/o the pressure relief valve and you simply cut in a tee in the hot line, put in a piece of pipe long enough to accomodate the probe and a female adapter.

                Note: This does not mean that i agree that it needs it, but the code that most municipalities in my area refer to does not make any distinction between tank heaters and tankless. However i generally know which will require me to install them and which understand the difference.

                Comment


                • #38
                  Re: Tankless flush

                  Rick that looks like a Tommy's burger.
                  ANYONE CAN TAKE THE HELM WHEN THE SEA IS CALM.

                  Comment


                  • #39
                    Re: Tankless flush

                    Originally posted by mtnman1100 View Post
                    Rick that looks like a Tommy's burger.
                    actually a "big tommys" burger. a knock off of the real tommys burger.

                    were you a local here before?

                    love the chili burgers and also the in-n-out burgers.

                    just ask josh

                    rick.
                    phoebe it is

                    Comment


                    • #40
                      Re: Tankless flush

                      I know this post is a year old. I was wondering if any of your plumbing codes have addressed the issue of installing the T&P over a PRV and such. I just was reading the updated Illinois Plumbing code.


                      Indirect, external, tankless or submerged coils used in heating water shall be equipped with a thermostatic mixing valve or valves when not connected to a storage tank. A pressure relief valve shall be installed on the cold water inlet of the tank. A properly sized temperature and pressure relief valve, based upon the energy input rating of the coils, shall be installed on the tempered line with the temperature sensing element immersed in the tempered water line as close as possible to the mixing valve.

                      Direct Fired Instantaneous Heaters. (Storage tank of more than 64 fluid ounces.) Direct fired instantaneous water heaters shall be equipped with a thermostatic mixing valve or valves which conform to ASSE 1017-1999. A pressure relief valve shall be installed on or adjacent to the heater. A properly sized temperature and pressure relief valve, based upon the energy input rating of the heater, shall be installed on the tempered line with the temperature sensing element immersed in the tempered water line as close as possible to the mixing valve.
                      Ron Hasil Lic #058-160417
                      A-Archer Sewer & Plumbing specializing in:
                      Tankless Water Heaters | Drain and Sewer Cleaning
                      Sump and Ejector Pumps | Backflow RPZ Testing

                      Comment


                      • #41
                        My jobs will have all protections afforded

                        I don't give two ***** what any mfg. spec has to say or even plumbing codes in my state or any other,


                        Any tankless water heater I install will be fitted with a T&P relief valve because it takes just one malfunction of that unit, sitting there with a broken flow switch or any myriad of problems that allows that unit to sit and cook the water and something bad will happen. It's guaranteed. These units are not foolproof, never will be.


                        Same with a thermal expansion tank; the second you shut that tankless unit down, you have 100 degree+ water sitting in XX linear feet of piping, and pex/cpvc has expansion rates since those products contract and expand, unlike copper or metallic piping.


                        Remember folks,

                        Plumbing codes are set to minimum standard of requirement. Just because the book says so doesn't mean you shouldn't think outside of the written equation.

                        The last thing I'll ever do is always trust the written words of a mfg. to understand all situations probable in potable water systems whether residential/commercial/industrial.

                        There is no denying that heated water equates to thermal expansion. Empty the entire hot water lines in a house and figure up the # of gallons and tell me if you can pour that into a sealed vessel and not have thermal expansion.

                        That's exactly what you have in the water line system until someone opens a faucet, flushes a toilet, operates a plumbing fixture requiring water.
                        Northern Kentucky Plumbers Twitter Feed | Plumbing Videos

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