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Dunham 640 Air Eliminator

Col08 Member Posts: 5
Looking for some help on this air eliminator, the vent on top went bad and a repairman just plugged it. Is there a replacement vent available or should I replace the entire air eliminator? Thread size on the vent is 3/8". Since plugging up this piece, been noticing the radiators aren't heating up, so I know we have trapped air in the pipes. I have been replacing the traps on each radiator with new caged units. Also, next to the air eliminator, are these 3 traps on the return lines, been noticing the outside 2 traps and pipes are hot, but the middle one is always cold, so thinking that trap is bad too? Thanks for the help.


    EBEBRATT-Ed Member Posts: 13,146
    The 3 traps in the picture are "crossover traps" those need to be working for the system to work. They can fail open or closed. I would replace the internals.

    keep the Dunham air eliminator and put vents on top.Put a tee on and use two Gorton #2s

    Others will coment
  • Steamhead
    Steamhead Member Posts: 15,765
    edited May 2021
    @Col08 , that vent is the only air vent in the system. No wonder the radiators aren't heating properly- if the air can't get out, the steam can't get in. Put a Gorton #2 where the plug is, and add a second one if needed. And don't let that "repairman" anywhere near your house again.

    The three traps act as vents to let air out of the steam main so the steam can distribute quickly. This reduces fuel consumption. Dunham, as MEPCO, still makes repair kits for most of their traps. Or you can use a kit from Tunstall or Barnes & Jones.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Col08
    Col08 Member Posts: 5
    All this happened after the lp gas valve on the boiler failed to shut off the heat. Temperature got to 103  before we could shut off the gas to the boiler. Ended up cracking the boiler, so the repairman put in solder seal, and fixed the seams, but I am still loosing alot of water. After all this, boiler wasn't still heating up right, so he plugged the air eliminator, then turned up the pressure on the boiler. We were getting some heat, but not like it was before. Also noticed that the valves on the radiators were all leaking too, so thinking the excess heat caused the valves and traps to fail. I have since turned down the pressure on the boiler and am looking at replacing it before winter comes. I did order the Gorton #2s today, and want to thank everyone for the help. 
    EBEBRATT-Ed Member Posts: 13,146

    You have all summer to get this right. You need the right contractor which is a steam contractor, not all plumbers and HVAC techs know steam.

    Check "find a contractor" on this site and post your location. Someone may have a recommendation. With a vapor system you need the right guy
  • mattmia2
    mattmia2 Member Posts: 7,194
    Even a lot of people that know the basics of steam won't take the time to research and think through this one. You need someone that does steam all the time and is good at it.