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European valve and MPT fitting

I've got myson thermostatic valve which apparently does not have tapered threads. When I thread a brass MPT fitting into it the fitting easily threads all the way in by hand until it bottoms out.

Do I need a different fitting, or should I just be applying extra dope/tape?


  • Kal Row
    Kal Row Member Posts: 1,520
    are you sure that

    it's not a compression, flair, or designed to go with a matching piece from the same manufacturer – with an o-ring at the end? – lots of folks have something like that

    otherwise tape away (5 turns) but also put Teflon paste on both sides - to make it a sure thing, and keep the tape from tearing as it goes in
  • Tom Meyer
    Tom Meyer Member Posts: 300
    European vs American pipe sizing

    This may not be the problem, but a good place to remind everyone....European pipe sizing and American pipe sizing are not the same. European is typically in metric, but it is OUTSIDE DIAMETER. American pipe sizing is nominal INSIDE DIAMETER.

    Tom Meyer
    Senior Designer/Trainer
    Precision Hydronics Corp
  • Kal Row
    Kal Row Member Posts: 1,520
    there was this nice italian lady at ISH

    displaying really nice and inexpensive flat plate heat exchangers made in italy, but they we all eropean thread,

    anyone know who make NPT adapters for this stuff?
  • Tom Giedraitis
    Tom Giedraitis Member Posts: 44


    It's definitely made to accept a nipple.
    The guy that sold me the valve and panel radiator told me to just use rectorseal, but I can't see that holding without a few turns of tape.

    Appreciate the feedback.
  • jim sokolovic
    jim sokolovic Member Posts: 439
    European adapters...

    Our company buys a lot of miscellaneous items by catelog from McMaster-Carr Supply company in New Jersey. Phone # is (732)329-3200. Everything is overpriced, but they stock alot of unusual items, especially adapters. Hope this helps.
  • Kal Row
    Kal Row Member Posts: 1,520

    seems like an opportunity - for a cottage industry,
    danfoss literally has 2 plants for euro and for usa stuff
  • Ball Valve
    Ball Valve Member Posts: 18
    euro pipe threads

    Heard of a similar problem at our company a few years ago on a paper machine at IP. Wound up threading the pipe together by hand as far as possible and then back-welding the fittings to get to IPT of the American variety.
  • Aidan (UK)
    Aidan (UK) Member Posts: 290

    I've used Swagelok adaptors for NPT threads to Euro pipes. They also do the BSP threads to US pipe adaptors. Good kit.
  • jwade55_3
    jwade55_3 Member Posts: 166

    But at what cost the adaptors? Just interested what made them "nice".

  • David Woycio
    David Woycio Member Posts: 107

    Years ago when we installed a lot of these we used a drill bit (forget what exact size.....64ths I think) to machine out a small amount of the US sized coupling or whatever fitting we were using and then sweat to the Myson piping. Worked great and never had a problem. Hope this helps.
  • Jack, CVMS
    Jack, CVMS Member Posts: 81
    BSP vs IPT

    That reminded me of the time I was doing some heat recovery connections for a co-gen system. The engine was a diesel of British manufacure, so all the threaded fittings were BSP. That was the first time I ever used Expando, and the last. But those fittings are still holding glycol without a sign of a leak.

    I thought we Americans were stubborn in resisting metrification, but the British have us beat. BSP, Whitworth, BSF, and who knows what else. At least our SAE & USS sizes both use the same size wrench to turn them. :^))
  • Aidan (UK)
    Aidan (UK) Member Posts: 290
    Not cheap.

    Not cheap, but the quality was self evident and I wasn't paying for them. They were imports from the US so I hope your prices are not shocking. They had a catalogue of adaptors for just about every obscure thread and fitting you could think of and the warehouse in London had them all in stock. Used in petro-chem. I doubt that they do chrome-plated ones.
This discussion has been closed.