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Raditor Threads not matching

PhillyRow Member Posts: 2

This is my first post. I recently bought a 1930's house with one-pipe steam, so I am still a novice.

Last week, I bought some radiators on craigslist to replace some smaller ones that were under-performing.

But, when I got them into place and tried to connect them to the (angle intake) valve, the threads do not seem to match. The difference on one is so slight that it seems to tighten, only to slip at the last minute. The other will not begin to thread, but is very close.

I see that the angle valves come in different sizes, but the difference does not seem to be 1/4". What do I need to do to be able to use these replacement radiators?

I appreciate any suggestions. Thanks.


  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
    edited August 2009
    Angle valves

    Angle valves come with 3 parts: valve, nut and spud.  The threads on the valve (where you screw on the nut) are not standardized and differ with manufacturers.  You will need to remove the spud and nut from the radiator and use the one that is correctly mated with a valve.  I'd go buy a new valve.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • PhillyRow
    PhillyRow Member Posts: 2
    Thank you

    This was a quick and clear reply.

    Thank you.
  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,576
    underperforming radiators

    how were some of the radiators "underperforming"? it is unlikely that they are clogged with debris, so there must be some other issue. check your main line  and radiator] venting, to make sure that the supply is not airbound as steam is rising. also check your pressure to make sure it is not set so high as to prevent the vents from doing their job. do this before spending more money on the radiators that instead should probably go towards new vents.

    you would certainly benefit from a copy of "the lost art of steam heating", available here. this will point you in the right direction when problems arise, and prevent you from barking up the wrong tree, as may be the case here.--nbc
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