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Dunahm Air Eliminator replacement available

Dave in QCA
Dave in QCA Member Posts: 1,764
I found a substitute for the Dunham Air Eliminator and wanted to post the information for all to see. Of course, it would also work for any system that used a float type air eliminator on the return piping of a 2-pipe vapor system, such as ARCO, etc.

The device is made by Spirax-Sarco, and is intended for use in hydronic systems to let air out of places where it might be trapped, but then closes via the float valve when water is present.

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I do not know the diameter for the valve port passage and if it is too small, it might not provide for enough venting. However, if operated in vacuum by adding a swing check valve, venting becomes less of a concern.
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.


  • JStar
    JStar Member Posts: 2,752
    Air Eliminator

    Awesome find! For that price, I'll try it on the next job. We would easily spend that much money on a bunch of Gorton #2's anyway. The only drawback is that it would not hold back steam if a few return traps went bad.
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