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ID Help: Unknown trap and element.

usp55 Member Posts: 2
Hi Folks, 1940 home with a wonderful steam system started giving me trouble. Two of my rads won’t heat fully. Took the element out of one of the traps and it heated right up so I think the element failed in the closed position. Problem is I can’t find a replacement element like it anywhere. Also can’t really identify the type of trap. It’s only marking is an “H” so I assume it’s a Hoffman though it’s profile doesn’t match the common ones I find online. Can anyone confirm the trap and or point me towards a replacement trap element?


  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    Here is an old Hoffman publication. Look on page 11. I am pretty sure you will not be able to get an exact element, but Barnes and Jones or Tunstall would make cage inserts to do the job. https://heatinghelp.com/assets/documents/Hoffman-Heating-Equipment.pdf
    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.
  • Steamhead
    Steamhead Member Posts: 16,727
    That might be a Hoffman #8. See if you can find one that hasn't been painted over- info should be on the top of the cover.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Gordo
    Gordo Member Posts: 852
    For some information on the Hoffman #8 trap, start the video below at about 5:50. Does that look like what you have? Does your trap have an integral seat a or removable seat? There are a number of different B&J cage unit numbers for the various 1/2" Hoffman #8 traps (if that is what you have). There is one called the 8H which lists a cage unit # of 4149

    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
    Dave in QCA
    EBEBRATT-Ed Member Posts: 15,329
    If you can't find parts you could replace the trap. Piping may or may not line up.

    Caution running with the trap parts removed will put steam in the return line and could damage other traps
  • usp55
    usp55 Member Posts: 2
    edited February 2019
    Thank you all. Seriously, great information.

    Yup it is a No 8. Pic below of a very faint stamping on the cap once the paint was removed. Integral seat.

    While I’d love to move to another trap I agree with Ed, I’d be lucky if the existing lines matched.

    Looking for the right replacement unit now. Ordered the tuntal on a whim a day or two before posting my first message. Realized when they arrived today that I bought the threaded or wrong one for my application. Think this is the one I need:


    QUESTION: What does the “1/2 inch” reference? Size of the insert? Size of the connecting pipes? I ask because I have 3/4” pipes. Out of the bottom of the trap. The original insert is 1-3/8” itself.

    Wondering if I have the 8c the with the 3/4” return. Going to get the tougher paint stripper out and really clean it off.
  • Sailah
    Sailah Member Posts: 826
    You sure that's 3/4" pipe? Hoffman never made a no 8 in 3/4 only 1/2" pipe.

    Barnes and Jones 2168, integral seat, reuse existing cover.

    The threaded insert is not correct for this trap.
    Peter Owens