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Snowmelt
Snowmelt Member Posts: 1,418
I’m always second guessing myself, this is on a navien

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  • Ironman
    Ironman Member Posts: 7,400
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    Other than the Tee being a little close to the Ell, what's wrong with it?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,849
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    If there is a pump in the boiler yes. Can.t see it working otherwise.
  • Ironman
    Ironman Member Posts: 7,400
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    If there is a pump in the boiler yes. Can.t see it working otherwise.

    There is.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • Snowmelt
    Snowmelt Member Posts: 1,418
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    I don't like the manifold that navian has, I also don't like the webstone service valves. id rather install a brass tee off the unit then a nipple then a shut off for flushing the unit. if I wanted I could add a union. then make it a 1 1/4 off the shut off , that's what navien manifolds do.
  • hot_rod
    hot_rod Member Posts: 22,505
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    Really shouldn't need flush valves on the heating side of the boiler? Although that valve does make the transition from boiler to copper. A nut and tailpiece can get you to 3/4 or 1" copper with a union.

    Try to keep a bit more distance between the tee and any ells or other fittings.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Snowmelt
    Snowmelt Member Posts: 1,418
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    hot rod there 1 inch nipples coming out of machine, I wanted to go to 1 1/4
  • hot_rod
    hot_rod Member Posts: 22,505
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    Snowmelt said:

    hot rod there 1 inch nipples coming out of machine, I wanted to go to 1 1/4

    What size boiler that you need 1-1/4" :)

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • kcopp
    kcopp Member Posts: 4,452
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    Why 1 1/4"?... seems overkill
  • Snowmelt
    Snowmelt Member Posts: 1,418
    edited December 2018
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    just from my understanding anything over 100,000 btu require 10 gpm , 10 gpm at 2 - 4 feet per second is boarderline 1 inch but 1 1/4 will do. the navien 240 is 120,000 BTU on heating side
  • HVACNUT
    HVACNUT Member Posts: 5,895
    edited December 2018
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    With modulation and the Tee's, you'll probably never see all the BTU's going through the secondary manifolds.
  • Gordy
    Gordy Member Posts: 9,546
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    If the boiler connection is 1”.
  • Ironman
    Ironman Member Posts: 7,400
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    Snowmelt said:

    just from my understanding anything over 100,000 btu require 10 gpm , 10 gpm at 2 - 4 feet per second is boarderline 1 inch but 1 1/4 will do. the navien 240 is 120,000 BTU on heating side

    That 120,000 can be a misleading number. You'll get that when you have a 50* delta T between the boiler and the system (think radiant slab), but not with high temp emitters (baseboards). The onboard circulator is only good for about 5 gpm.

    Always size piping off of gpm, not btus. The btus, when plugged in to the universal hydronics formula, will tell you how many gpm is required. In this case, that's already been determined by the circ that comes on the boiler.

    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Gordy
  • Snowmelt
    Snowmelt Member Posts: 1,418
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    your right Gordy they are one inch, I do want to educate myself so I am going to ask, even though its 1 inch and I am pretty sure the heat exchanger on the navien combo has a high head pressure with that statement. I am going to say that the internal pump doesn't have a lot of GPM I am thinking 3 - 4, if I increase the pipe diameter I think I can squeeze 6 GPM out of the machine.
  • Snowmelt
    Snowmelt Member Posts: 1,418
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    iron man, thats why I want to increase the pipe size
  • Ironman
    Ironman Member Posts: 7,400
    edited December 2018
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    I really don't think that changing a couple of feet of 1" pipe is gonna make a bit of difference.

    At 5 gpm, those two short lengths of 1" have a head loss of 0.04.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    DZorokcopp
  • Snowmelt
    Snowmelt Member Posts: 1,418
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    I actually seen it work , I replaced about 6 foot of 3/4 pipe with 1 inch and I gained 3/4 of a GPM every little bit counts
  • Gordy
    Gordy Member Posts: 9,546
    edited December 2018
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    The boilers supply, and return piping are 1” because they know you won’t squeeze more than 5gpm through the HX with the onboard circ. Like @oronman said.