main vent on old steam system

Andy Wyatt

I recently saw a vented steam system. It was as one pipe system but instead of using individual vents on each radiator there was a 1/4" iron pipe vent line that used the same tapping. each radiator had one and they returned to a common vent above the boiler's main return line. The vent was very old and quite unusual. I can't imagine that it is working properly. When I first fired up the unit it came up to pressure and shut off the burners before the feed pipe even got warm. Has anyone seen or heard of this before? If so can I replace the vent with a Hoffman Main line vent?

Unknown

That's a Paul system

It kept the water and odors that are sometimes present on one pipe air vents inside the system.

Put a nice, big capacity, main vent on the system. It'll work like a champ, if everything else is up to snuff.

Noel

Mad Dog

Andy, that sounds like it could have been a Pall system

or some crude adaptation of it. If I do remember correctly, The Pall system had all the radiator vents commonly connected together and terminated in the chimney flue. It was a natural vacuum system. As the chimney drafted, the negative pressure drew the air out on the rads, letting the steam enter, and the exhausted air went up the chimney. Please!!!! Take pictures and put 'em up...The Deadmen and the Living Deadmen (Me, Steamhead, Noel, and Dan, Boilerpro) will rejoice!!!!!!!!!! Mad Dog

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Steamhead

It also could be an Eddy system

which had a similar configuration.

Instead of using a main vent on those air-return lines, I'd see if the existing "vent" was actually a water- or steam-driven ejector (works like a jet pump). If not, I'd make up an ejector out of some pipe fittings, and drive it with a small air pump wired to run whenever the burner starts. This will create a vacuum in the air lines, which is the way the Dead Men originally designed that system to work.

I think you can still get Paul radiator vents from Hoffman Specialty. You can use ordinary thermostatic radiator traps for your main vents and hook them into the air lines too. You could also put a check valve just before the ejector and run the system in vacuum!

I'd also love to see some pictures! Where is this system located?

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