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old bottom nipple connected (one pipe steam style) radiator holding condensate

in a building with steam supplied from a utilities connection , i have an old radiator (see pics). with a TRV installed.
it is collecting condensate (and therefore hammering). i assume it is from the trv closing , then the radiator forming a vacuum, then the radiator sucking in its own condensate and more condensate from an end of main drip trap that runs right under it (see pic).
My thought was to use another thermostatic trap as an equalizer . i was going to connect a half inch pipe from the elbow after the valve to the condensate line just before the wall. i was hoping this would equalize the ends of the radiator and allow the condensate to flow out./// This idea comes from the piping scheme that one might see on an air handler coil, to allow it to drain once the control valve has shut. This perimeter heat system is on a vacuum pump, so i can't just add a vacuum breaker.//// Does this seem like a good idea, only option, better suggestions from the gallery????????????? thanks.


  • cashheatandactech1cashheatandactech1 Posts: 10Member
    here are some pics.

  • Dave in QCADave in QCA Posts: 1,736Member
    Have you made sure that the thermostatic trap on the drip leg of the riser drop is working correctly and closing. My first guess would be that it is the culprit. If it was leaking steam, it would do exactly what you are describing.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
  • EBEBRATT-EdEBEBRATT-Ed Posts: 5,634Member
    What you have is fine and shouldn't hammer if the traps and the trv is working correctley
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