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1" G thread tailpieces

hot_rod
hot_rod Member Posts: 18,195
More and more you will see components with the 1" G thread. This thread is commonly used on 3 way mixing valves. You see this connection inside many mod con boilers also, valves, pumps, etc.
At Caleffi there are 15 different products that install with a 1" G thread.
Here are 31 versions of the tailpieces available 1/2- 1. Sweat, press, NPT and both pex connections. Check valve versions also.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
Erin Holohan Haskellkcopp

Comments

  • lkstdl
    lkstdl Member Posts: 29
    Does Caleffi also offer tailpieces for 2" G thread?
    Luke Stodola
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,935
    edited February 2021
    Who names these things? Is only the female side called the G fitting? Are they difficult to find? Plumbers have to get their minds out of the bedroom and back in the mechanical room!
    Edward Young Retired HVAC Contractor & HYDRONICIAN Services first oil burner at age 16 P/T trainer for EH-CC.org
  • Steamhead
    Steamhead Member Posts: 15,755

    Who names these things? Is only the female side called the G fitting?

    And what, exactly, does "G-thread" mean in this application? A certain thread pitch, maybe?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • lkstdl
    lkstdl Member Posts: 29
    Its not actually called "G-thread", it is normally written as G followed by the nominal size (in inches). G1, G2 etc.

    It is BSPP (British Standard Pipe, Parallel) aka ISO 228. Straight threads rather than tapered, with a gasket making the seal.
    Luke Stodola
  • hot_rod
    hot_rod Member Posts: 18,195
    lkstdl said:

    Does Caleffi also offer tailpieces for 2" G thread?

    2" MIP, or sweat, press?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • lkstdl
    lkstdl Member Posts: 29
    In this particular case I am looking for something with female G2 and female 2" NPT, but if you just offer the MIP I could certainly use a coupler. I am considering buying some Grundfos pumps off eBay but they have G2 threads instead of flanges. I'm guessing that's a European thing? If I understand it correctly, your tailpieces essentially functions like a union, and would allow easy replacement of the pump without the need for flanges.



    I could certainly just stick with a standard flanged pump, but if you are saying we'll see these connections more and more maybe its a safe bet.

    Thanks!

    Luke Stodola
  • hot_rod
    hot_rod Member Posts: 18,195
    Looks like a 2" nut, thread OD would be about 2-1/4, like this.
    Biggest fitting that will go thru that nut would be a 1-1/2 NPT or sweat. If you find a 2" NPT or sweat tail it will be a drop nut style, since it is too large to fit thru the nut..

    Caleffi F000094 is a 1-1/2" sweat tailpiece with fiber washer
    2" nut is R53003
    NA 10715 is a 1-1/2 press tailpiece.

    Be careful buying Euro stuff, it will be most likely be 230V 50 Hz, although it does seem to run on 240V, a hot and neutral leg. I see on some recent Euro pumps 208- 240V, 50- 60Hz on the label.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    lkstdl
  • lkstdl
    lkstdl Member Posts: 29
    Thank you! Exactly what I was looking for. Still may end up sticking with a US model though to make any future swap-outs easier.
    Luke Stodola
  • hot_rod
    hot_rod Member Posts: 18,195

    Can I ask why? Does npt not work anymore? Any reason to complicate threads of all things? 

    NPT works fine, why wouldn't it? Although the US is one of the few places it is used extensively. Straight threads and hemp is the go to in most of the world for assembling threaded pipe. Once you get use to it is actually is very accurate as the thread "make up"is not dependent on the thread length or quality. You end up exactly where you want to be on length.
    The G thread and tailpieces give you an easily serviced joint for pumps, valves, boilers.
    Again the US and Canada is about the only flanged circulator market. You see that straight thread connection on pretty much every Euro based boiler.
    The automotive industry went metric without the sky falling, the heating industry could also :)
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream