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  • #16
    Re: can I add a zone like this?

    Originally posted by Flux View Post
    Not to hijack the thread, but NH are you a zone valve fan or do you like doing them with circulators? We personally like using zone valves. Have you used Grundfos circulators before? if so, how do you like them, and do you like them over Taco?
    Grundfos puts Taco to shame in both performance and cost. With the reverted flanges there is no reason for me to ever install another Taco.

    I also prefer to use zone valves and the right pump. My experience with zone pumps has been an ongoing saga of ghost flow. Yes, the loops have check valves installed and still ghost flow.

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    • #17
      Re: can I add a zone like this?

      Originally posted by Kevin Jones View Post
      All three diagrams are wrong. I see the primary/secondary situation and you must still be the water. Water has no desire to jump a tee, feed the baseboard properly, and return. It would much rather skip the heating element and go back to the boiler.

      At the end of the supply line run a pressure differential bypass valve needs to be added. This will provide the resistance needed for the system to work properly. As for the remainder of the layout I don't know current pump or pipe size. I don't know baseboard size in order to establish a gpm flow. All those questions need answers to help more.

      From the diagrams you need one properly sized pump on the secondary loop and a pressure bypass. Then adding a loop is nothing more than a T-stat, zone valve, pipe from supply to return, use a boiler tee with plug/cap on the return side of the new loop for air discharge, and adjustment of the pressure bypass.
      Wrong wrong wrong who taught you?
      There are many design possibilities and choices
      Since you like Grundfos so much, I included a drawing of theirs with a boiler pump and system pump

      Water doesn't "jump tees" the circulator creates positive & negative pressure to overcome friction of the piping system to circulate (not pump) water.

      NH said it earlier, boiler flow requirement must differ from system flow/head requirements.

      If you have ghost, mystery, migration or gravity flow with checks, one of two things are wrong, 1. piping (separation of supply and returns) 2. adjacent circs are too big for the zone they are on.

      1 circ with zone valves is not the cure all.
      What about a house with 8 zones requiring 16 GPM total and only one zone is calling, wait don't tell me, I already know, noise, air, low Delta T. Variable speed Delta T or P circulator would be the fit perhaps.
      Attached Files

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      • #18
        Re: can I add a zone like this?

        Originally posted by Lee H View Post
        Wrong wrong wrong who taught you?
        There are many design possibilities and choices
        Since you like Grundfos so much, I included a drawing of theirs with a boiler pump and system pump

        Water doesn't "jump tees" the circulator creates positive & negative pressure to overcome friction of the piping system to circulate (not pump) water.

        NH said it earlier, boiler flow requirement must differ from system flow/head requirements.

        If you have ghost, mystery, migration or gravity flow with checks, one of two things are wrong, 1. piping (separation of supply and returns) 2. adjacent circs are too big for the zone they are on.

        1 circ with zone valves is not the cure all.
        What about a house with 8 zones requiring 16 GPM total and only one zone is calling, wait don't tell me, I already know, noise, air, low Delta T. Variable speed Delta T or P circulator would be the fit perhaps.
        Back up...Right, Right, Right!
        The design given shows a T system. I fully understand the Delta P. Do you? If the delta P across the element is greater than the secondary loop then the element will be mostly bypassed. YES A PRESSURE DIFFERENTIAL BYPASS IS A CORRECT and simple solution.

        Funny you say 8 zones and 16 gpm because that is my house exactly. Difference is my 8 zones are manifolded further into infloor.

        I have already said there is no way to size the system based on the information given. I did say that the drawings given are wrong.

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        • #19
          Re: can I add a zone like this?

          I agree that ghost flow is a result of improper design. The systems that I have had to fix with this isuue are also inherited. I find that the use of zone valves with the right pump or pumps depending on design works much better in general and is less costly to repair than zone pump situations.

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          • #20
            Re: can I add a zone like this?

            Diagram 1 is t'd also. End or side run makes no difference in that single secondary circuit design.

            P/S piping lets several circulators of different pumping ability "co-exist" within the same system without interfering with each other.
            Primary/Secondary doesn't always dictate closely spaced tee's. There are also Parallel primary systems when all secondary zones must see even water temps, regardless of flow differences for example and so on.

            Water doesnt bypass a T to follow short flow, it is attracted to lower pressures, via the inlet of a circulator, creating flow from highest to lowest pressure points. Thus the secondary circuit going to his rads will see the flow desired based on circ, pipe, ftgs, valves, etc.

            I can and will argue this all day long as I work for a leading boiler manufacturer as an engineer.

            Comment


            • #21
              Re: can I add a zone like this?

              Originally posted by Lee H View Post
              Wrong wrong wrong who taught you?
              There are many design possibilities and choices
              Since you like Grundfos so much, I included a drawing of theirs with a boiler pump and system pump

              Water doesn't "jump tees" the circulator creates positive & negative pressure to overcome friction of the piping system to circulate (not pump) water.

              NH said it earlier, boiler flow requirement must differ from system flow/head requirements.

              If you have ghost, mystery, migration or gravity flow with checks, one of two things are wrong, 1. piping (separation of supply and returns) 2. adjacent circs are too big for the zone they are on.

              1 circ with zone valves is not the cure all.
              What about a house with 8 zones requiring 16 GPM total and only one zone is calling, wait don't tell me, I already know, noise, air, low Delta T. Variable speed Delta T or P circulator would be the fit perhaps.
              Even the factory zone pump pipe system you are displaying can be done with consequences if the common return pipe to the primary loop is not sized properly. If that is piped by a layman with all 3/4" pipe for 3 returns and continues to a 3/4" pipe going to the primary loop then the pipe will fail from overvelocity.

              I used the term "jumping t" for the layman to understand. Should I just use shop talk so only a few can understand? If the person asking already understood...why would he be asking?

              Comment


              • #22
                Re: can I add a zone like this?

                Originally posted by Lee H View Post
                Diagram 1 is t'd also. End or side run makes no difference in that single secondary circuit design.

                P/S piping lets several circulators of different pumping ability "co-exist" within the same system without interfering with each other.
                Primary/Secondary doesn't always dictate closely spaced tee's. There are also Parallel primary systems when all secondary zones must see even water temps, regardless of flow differences for example and so on.

                Water doesnt bypass a T to follow short flow, it is attracted to lower pressures, via the inlet of a circulator, creating flow from highest to lowest pressure points. Thus the secondary circuit going to his rads will see the flow desired based on circ, pipe, ftgs, valves, etc.

                I can and will argue this all day long as I work for a leading boiler manufacturer as an engineer.
                Wonderful!

                So what is the C of V difference between a 40' of 1" secondary loop and the 3 pieces of 8' 3/4" baseboard that run up and down from the crawlspace...or should we make it 1/2". The water will loop away from the element run and take the path of least resistance. ie...It doesn't want to jump the loop. A pressure bypass will makeup for errors from the original design work.

                Comment


                • #23
                  Re: can I add a zone like this?

                  I think you mean CV-Flow coefficient

                  Pipes that go up and down are equalized in a closed system, its only the friction of the pipe at a given temp/viscosity/flow/pressure.

                  You said it earlier, we dont know all the circumstances of the OP's system, just designs and nothing wrong with #1 (BTW, thats what he has had for many years)

                  With your advice, perhaps all the manucfactures with high head/high efficient boilers should heed your advice, remove our primary boiler pumps and install your selected pump with zone valves and a presure by-pass.

                  Comment


                  • #24
                    Re: can I add a zone like this?

                    Originally posted by Lee H View Post
                    I think you mean CV-Flow coefficient

                    Pipes that go up and down are equalized in a closed system, its only the friction of the pipe at a given temp/viscosity/flow/pressure.

                    You said it earlier, we dont know all the circumstances of the OP's system, just designs and nothing wrong with #1 (BTW, thats what he has had for many years)

                    With your advice, perhaps all the manucfactures with high head/high efficient boilers should heed your advice, remove our primary boiler pumps and install your selected pump with zone valves and a presure by-pass.
                    You said it already that you work for a major as an engineer. As such you know that mod/cons only run high eff. in colder runs. Why not do away with primary on single temp infloor systems? The primary was mostly for cold shocking high mass units and running multi-temp systems. Why not do away with it on mod/con all high temp. situations? Cold shocking is not a worry. Condensate no problem. So please explain why in single temp. load designs on a mod/con one would truely rquire a P/S.

                    You also know that with a regulator at the end of the supply run...a better gpm flow rate is gained across all the loops...baseboard, rads...

                    Some mod/cons do have issues with overshooting max temp. on short loop zones. This will cause a soft error code.

                    Comment


                    • #25
                      Re: can I add a zone like this?

                      Primary/secondary while years ago was used as a forced boiler bypass, it's purpose and always has been to provide proper flow through the boiler. Take for instance a large copper tube boiler that may be supplying a small or micro zone, you know well as I there is a minimum flow/temp rise required.

                      Think of the newer mod-cons just the opposite, they have lower flowrates or much higher head than most systems, thus the need to decouple these units also from system flow.

                      With primary/secondary the heat transfer is done with higher boiler delta temps.
                      Last edited by Lee H; 07-22-2010, 08:17 PM.

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                      • #26
                        Re: can I add a zone like this?

                        "You also know that with a regulator at the end of the supply run...a better gpm flow rate is gained across all the loops...baseboard, rads..."

                        Yes but only if the flow characteristics of the system changes. No need to adjust for flow changes as long as it can't or won't change. With the onslaught of different circs available today along with multi-speeds, a designer can dial in the right flow.

                        Now I suppose if TRV's are installed on the rads, a bypass or a better yet a variable circulator should be considered. However, with a good piping system such as 2-pipe reverse return, should 1 or 2 rads get satisfied before the main stat, most systems could devide the flow amongst the others with minimal system effects.

                        Comment


                        • #27
                          Re: can I add a zone like this?

                          Originally posted by Lee H View Post
                          Primary/secondary while years ago was used as a forced boiler bypass, it's purpose and always has been to provide proper flow through the boiler. Take for instance a large copper tube boiler that may be supplying a small or micro zone, you know well as I there is a minimum flow/temp rise required.

                          Think of the newer mod-cons just the opposite, they have lower flowrates than most systems, thus the need to decouple these units also from system flow.

                          With primary/secondary the heat transfer is done with higher boiler delta temps.
                          Many of the mod/cons don't care about delta T, the issue is the CV. Thus calling for a Grundfos 26-99 type pump to run the head loss and falling back on sensors to modulate BTU input, thereby stabalizing delta T.
                          They work better with a higher delta T...done.
                          They are low mass...so reaching temp quickly is not much of an issue. They exceed the rate of the old high mass from startup. We also now have outdoor input which should keep the unit running more steadily if setup correctly.

                          Comment


                          • #28
                            Re: can I add a zone like this?

                            Actually we care about DT, as it is how they function and the bigger the better, as it raises comb efficiency.

                            It's all about the cool return temps for mod-cons

                            Comment


                            • #29
                              Re: can I add a zone like this?

                              Originally posted by Lee H View Post
                              "You also know that with a regulator at the end of the supply run...a better gpm flow rate is gained across all the loops...baseboard, rads..."

                              Yes but only if the flow characteristics of the system changes. No need to adjust for flow changes as long as it can't or won't change. With the onslaught of different circs available today along with multi-speeds, a designer can dial in the right flow.

                              Now I suppose if TRV's are installed on the rads, a bypass or a better yet a variable circulator should be considered. However, with a good piping system such as 2-pipe reverse return, should 1 or 2 rads get satisfied before the main stat, most systems could devide the flow amongst the others with minimal system effects.
                              One could use a Grundfos Alpha type pump and let it do the job. As long as the maximum output of that pump works for the design. I am currently using one of those pumps on a fully supplied solar home. This is a water system for domestic water and heat for 3500sq/ft. They are very happy with its performance.

                              As for the retrofit at hand I think the PD bypass is the simplest fix and allows for installation of another loop while maintaining system flow. Perhaps even better system flow than ever before.

                              None of us have seen the system. There are a plethora of installation errors on every type of system. Even still 10 systems installed exactly the same, will all have different issues. Every system has it's own personality.

                              Comment


                              • #30
                                Re: can I add a zone like this?

                                Originally posted by Lee H View Post
                                Actually we care about DT, as it is how they function and the bigger the better, as it raises comb efficiency.

                                It's all about the cool return temps for mod-cons
                                Exactly...and a P/S increases boiler temp return.

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