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What would you change?

JackW
JackW Member Posts: 236
I'm redoing my radiant heat system after my water heater took a dump. So I have installed a mini NG Tankless and am getting close to plumbing it up, the gas, intake and exhaust are done. It's a two zone system and about the only diagram I could find that is fairly simple is the one below, that I intend to use. What I would like to know is what if any changes would you make in this set up? I'm not going use two pressure relief valves and maybe not as many fill points. Unlike the picture my output and return manifolds will be mounted towards the bottom of my 4x8 sheet of plywood. One zone has four inputs and returns, the other two. Any thoughts and ideas on this diagram will be greatly appreciated.
Thanks,
Jack


Comments

  • Zman
    Zman Member Posts: 7,561
    I would not put the expansion tank directly under the air separator. The dirt tends to separate at that point as well and goes right onto the tank. If you offset the tank and put a drain point there you can blow out debris and check the tank charge without removing.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    JackW
  • JackW
    JackW Member Posts: 236
    Zman thank you so much. Does it matter what side the tank goes on? Not sure I understand where you would put the drain point
  • Zman
    Zman Member Posts: 7,561

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Intplm.
  • JackW
    JackW Member Posts: 236
    So just tee it off the output side of the air eliminator?
  • HVACNUT
    HVACNUT Member Posts: 5,804
    > @JackW said:
    > So just tee it off the output side of the air eliminator?

    No. Pipe it as shown in the diagram @Zman posted. There's a 1/2" tap at the bottom of the separator. Pipe it from there. Also your pic doesn't show the cold water feed for the boiler. That will get piped in at the same location between the separator and expansion tank.
    JackW
  • JackW
    JackW Member Posts: 236
    Oh I see, didn't get at first. Is that the cold water feed right below the separator, that can be just a 3/4" hose bibb can't it? Also what's the symbol at the bottom of the line mean? Thanks.
  • Intplm.
    Intplm. Member Posts: 1,883
    edited October 2019
    @Zman. Do you want @JackW to pipe the make up water between the air separator and the expansion tank too ?!👍🏼
    ZmanJackW
  • Intplm.
    Intplm. Member Posts: 1,883
    Intplm. said:

    @Zman. Do you want @JackW to pipe the make up water between the air separator and the expansion tank too ?!👍🏼

    @JackW . What I mean is to add a tee between the expansion tank and the air separator and have your automatic water feeder, feed the water there.
    JackW
  • JackW
    JackW Member Posts: 236
    I don't believe I'm going to have an automatic water feeder in my system. It's going to be a closed system if that means anything.
  • Intplm.
    Intplm. Member Posts: 1,883
    JackW said:

    I don't believe I'm going to have an automatic water feeder in my system. It's going to be a closed system if that means anything.

    How do you feed water to it. ?
    JackW
  • JackW
    JackW Member Posts: 236
    I plan on putting a valve at the pressure tank per the drawing Zman gave me. I'll admit I don't know what an automatic water feeder is.
  • DZoro
    DZoro Member Posts: 1,048
    Have you looked at the Lochinvar Noble boiler? Just don't care for a tankless in this application.
    JackW
  • JackW
    JackW Member Posts: 236
    Ouch. No I haven't, I've already bought the tankless.
  • DZoro
    DZoro Member Posts: 1,048
    Ok does the tankless have piping and pump flow specs in the manual? It should and they need to be followed closely. There should be full piping diagrams for you to follow.
    JackW
  • JackW
    JackW Member Posts: 236
    It's a Hydro Smart 120 Condensing Gas Micro Boiler. There is a diagram in the back that shows a basic one zone layout. Mine is a two zone layout so I would have to adapt it. There are some pictures of their packaged zone controls also.