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Looking for a part that connects the radiator to the valve

SethK Member Posts: 43
So, I think I know the name of the part I need, now that I've filled my search history with interesting terms. I think it's called a "male union tailpiece with nut." One side threads into a 1-5/8" hole in the radiator (technically into a reducer that seems to have become one with the radiator), the other side has a 2" threaded nut that makes a compression connection to an existing valve. (Both of those measurements are my best guesses as the male part is squashed the the nut is broken.)

Anyway, I can find small versions of that, or I can find complete replacement valves that come with that connector, but I can't find just that connector. Am I searching for the wrong term? Would a plumbing store carry this?



  • BobC
    BobC Member Posts: 5,478
    The valve and the part that threads into the radiator are sold as a set, both must be replaced at the same time because if they are not matched it will leak.


    A new valve may be shorter than what you have now so you may need an extender to make up the height if the pipe coming out of the floor wont reach the new valve.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    JUGHNE Member Posts: 11,061
    The part you were searching for is called the "radiator spud" and as BobC said they come with a new valve. Do you have the old spud out of the radiator? Try to pull up on the valve, you may have enough spring in the basement piping to account for the new slightly shorter valve.
  • SethK
    SethK Member Posts: 43
    Thanks, I should have known it wouldn't be that easy.

    I guess I need to try to get a spud back from the radiators I traded or just buy a new valve. A 1.5" valve is $135 at home dept (!!!) but a fraction of that online.
    JUGHNE Member Posts: 11,061
    edited April 2016
    If you have removed the existing spud you would know you might not want to take the chance on the 2nd spud fitting your valve. Sometimes spuds will unscrew and stay in one piece......more often not. I would get a new valve with it's new spud included. But first........

    IIWU.....I would first buy a spud wrench to get the old spud out of your rad (you will need it to install the new spud) the spud wrench may not get the old one out.....save the threaded end for size comparison. Also pick up a 1 1/2" threaded cap.
    Then with the boiler power switch off remove the valve from the riser pipe, you must use 2 pipe wrenches, probably need extenders on the wrenches. Don't want to crush the pipe near its threads. This might be easy or seem impossible. If the later check back here for more advice. If easy and you need the heat in the house on, cap the riser pipe . Take the remains of your spud to check its size at hardware store. If the 1 1/2" caps fits your pipe then you made a good guess and invested little money to be sure. Your old spud threads will confirm what goes into the rad. Occasionally they are different sizes.

    A fair quality 1 1/2" valve might cost 1/3 of what HD wants.
    Country of origin makes most of the difference.
    Made in USA......should be high quality & price
    Made in (ROC) Taiwan......pretty fair quality and price
    Made in China.......self explanatory

    Make sure you get a Steam valve, not hot water valve, (might look the same but has smaller passageway inside).