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hydraulic separator piping

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dobro23
dobro23 Member Posts: 72
in Plumbing
just wondering "in your opinion" what the correct placement of the expansion tank, water feeder, and boiler side circulator is when using a hydraulic separator. I have searched online and have found all configurations. my experience in the field has shown that these components are almost always on the return side of the boiler circuit between the separator and the boiler return with the expansion tank and feeder on the suction side of the boiler circulator. i assume this is safe but is it best? with conventional piping ie no separator, i generally put my zone circulator(s) on the supply of the boiler just after the expansion tank/feeder. wondering why the hydraulic separator seems to always be reversed in essence by pulling the water through it and pushing it back into the boiler. hope this makes sense. what do you guys think?

Comments

  • Steve Minnich
    Steve Minnich Member Posts: 2,868
    I like to try it different ways and honestly it's worked well each way I've tried it.


    Steve Minnich
  • hot_rod
    hot_rod Member Posts: 25,918
    Really not much difference. Wherever you connect the entire sep becomes the PONPC.

    On the multi boiler system with the large floor mount tanks, the expansion is connected at the end of the large headers off the sep.

    Avoid putting the tank directly below the bottom port of a separator as dirt and crud may settle onto the diaphragm in the expansion tank and cause wear.

    Here are some examples from Idronics 15.







    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Ironman
    Ironman Member Posts: 7,773
    Or, you can do it like this:
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    GordySteve MinnichPaul S_3
  • Gordy
    Gordy Member Posts: 9,546
    Well @Ironman that shoots the hell out of the debate of which is considered primary, and secondary side with the PONC as the focus....I like it.
  • hot_rod
    hot_rod Member Posts: 25,918
    Nice, creative. I like the exp tank mounted horizontal with that sturdy bracket. Hydro-Claw?

    You have the backflow correct also. They can only be vertical if flow is down.

    vi
    Ironman said:

    Or, you can do it like this:

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Ironman
    Ironman Member Posts: 7,773
    Yes, HydroClaw.
    I've heard some folks say that you're not supposed to mount the expansion tank that way, but I've never had a problem with it and can't find any documentation to say otherwise. Mark Eatherton says it's okay. That's good enough for me.

    If you think about it, a floor tank has the connection at the bottom, not the top.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • hot_rod
    hot_rod Member Posts: 25,918
    Ironman said:

    Yes, HydroClaw.
    I've heard some folks say that you're not supposed to mount the expansion tank that way, but I've never had a problem with it and can't find any documentation to say otherwise. Mark Eatherton says it's okay. That's good enough for me.

    If you think about it, a floor tank has the connection at the bottom, not the top.

    Page B3-5 in the Amtrol book indicates approved horizontal mount, if ever you get called out on it, or an inspector challenges you.


    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Steve Minnich
    Steve Minnich Member Posts: 2,868
    @Ironman - I do it all the time.
    Steve Minnich
  • Ironman
    Ironman Member Posts: 7,773
    hot rod said:

    Ironman said:

    Yes, HydroClaw.
    I've heard some folks say that you're not supposed to mount the expansion tank that way, but I've never had a problem with it and can't find any documentation to say otherwise. Mark Eatherton says it's okay. That's good enough for me.

    If you think about it, a floor tank has the connection at the bottom, not the top.

    Page B3-5 in the Amtrol book indicates approved horizontal mount, if ever you get called out on it, or an inspector challenges you.


    Thanks, Stephen!

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Farmer11
    Farmer11 Member Posts: 2

    hey guys,

    Thanks for the diagrams! Was helpful to confirm my configuration. One question, I can’t understand why they’ve installed a pipe connecting the supply and return to the floor heating. Is this correct?

    IMG_8723.jpeg
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 18,849

    I would say no if the circ is off when the zone valves are closed. If the circ runs all the time it should have a bypass valve installed in that pipe. Looks like they are using the small pipe for a pressure control.

  • hot_rod
    hot_rod Member Posts: 25,918

    that is not correct

    The supply from and return to the sep should not connect

    Install a valve or cut and cap. Take the handle off the valve after you turn it off!

    IMG_1135.jpeg
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Farmer11
    Farmer11 Member Posts: 2

    Thanks gentlemen! How about the pressure tank connection into the hydraulic separator? In the Calefacto CB100 connection diagram, nowhere does it show connecting into the bottom like that. Is it connected wrong?

  • GGross
    GGross Member Posts: 1,650
    edited October 8
    https://forum.heatinghelp.com/discussion/comment/1867133#Comment_1867133

    manufacturers of low loss headers will always tell you not to hook the tank there. The concern being that debris tends to settle in that spot and can settle in the tank and over time possibly disconnect the tank from the system, and can make flushing the debris out more difficult. In this case they did build a little dirt leg of sorts there, it's probably OK but I would prefer it on the return pipe (colder pipe) on the boiler side of the low loss header, not attached to the LLH directly. I will also add that there are many many installed like that in my area, it was really common and I was even taught to do it this way originally, a conversation with our local caleffi rep right around the time we picked up their LLH with magnetic dirt separation changed my mind. I even took the white out to my diagram and changed it right then! I've also seen them piped in sensor/gauge wells like what you have near the top of the LLH, that's a bit better than the bottom but that thread is usually not NPT, and why not just put a gauge there if taking the plug out?

    also im sure your pic is from service, but make sure that service valve to the exp tank is always open

    IMG_4345.jpg
    Farmer11
  • hot_rod
    hot_rod Member Posts: 25,918

    here are some piping options for an expansion tank on a sep

    While yours is not pic perfect, they did offset with a tee, so it is not directly below.

    I suppose it depends on how much debris will filter out and fall down to that connection

    IMG_1156.jpeg IMG_1155.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Farmer11

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