dunham air eliminator

stonedog

Is anyone familiar with the Dunham Air Eliminator (Model 220)? It is used at the end of the dry returns in my two-pipe low pressure steam heating system.I am looking to rebuild it.It is featured in Dunham literature as the air vent in their c.1940 "Vapor" sytem. Also,would an F&T trap combined with air vents replace it?

Steamhead (in transit)

It's basically a glorified main vent

that vents from the dry returns. A F&T trap will not replace it. The only thing inside is a float that will close the vent port if water rises too high. If the #220 unit will pass air out the vent, I find it easier to unscrew the vacuum check from the vent port (if it's still there) and install a Gorton #2 main vent in its place, than to pull the unit apart.

The steam mains on this system were probably vented thru radiator traps piped between the steam mains and the dry returns. These routed air from the mains to the dry returns, where it could escape from the #220 air eliminator. Make sure these traps are working or you'll get sluggish steam distribution.

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stonedog

dunham air eliminator

Steamhead
Many thanks for the reply.I am in fact rebuilding the traps (2) at the ends of mains right now.They are Dunham 1A
with the integral seats.Am using MEPCO 9606 capsules to rebuild.
The Air Eliminator has a copper float;the Eliminator is piped in parallel on the dry returns. Does the copper floar /shot-off merely keep condensate from leaking out of the air check valve or does it have another purpose?

Steamhead (in transit)

You're right, that's all the float does

keeps water from escaping if it backs up that far. Almost all steam main vents available today will do this too.

Vapor systems were the Cadillac of heating in their day and are still some of the best out there. I'm glad to see that you're restoring yours.

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