Vacuum Vent Valves for steam Radiators

Ted Burzynski

I currently have a vacuum steam heating system in my home and am in need of adding and replacing some of my radiator vacuum vent valves. I currently have Dole 2B and Hoffman 2A vent valves on the system. I'm also looking to
> replace the quick vent on the main header pipe which has a Dole 6B (3/4" pipe thread on it.) vent valve on it. It is my understanding that vacuum vent valves are no longer being manufactured. To the best of your knowledge, is there any place that I can pick up these vacuum vent valves,
or possibly modify say a regular steam vent valve by sweating a check valve on the end of it. It is imperative that I maintain the vacuum status of the system. Whatever recommendations you could make would be greatly appreciated. Thanking you for your time in this matter;
> Sincerely,
> Ted Burzynski

Steamhead

Vacuum

is problematic at best, Ted. If you don't get all the air out of the system on start-up, the remaining air can expand and block steam flow. This is one reason that type of radiator vent is no longer made. You can still get Hoffman #76 vacuum main vents though.

If that were my system I'd change over to straight steam vents.

What is the "imperative" reason you need vacuum? Maybe there's another way to do what you need to do.

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Ted Burzynski

Vacuum Vent Valves for Steam Radiators

There are two reasons that I want to maintain the vacuum part of the system; 1. Without them, when the boiler goes off and as soon as the water in the boiler starts to cool down, all the steam is drawn back to the boiler and all the radiators cool down immediately. With the vacuum valves, they'll stay hot giving off heat for 20 to 30 minutes after the boiler goes off. And 2. After the boiler has cooled off, since the vacuum valves will not let air into the system, the boiler is at a pretty good vacuum around 25" of vacuum. So, the next time the thermostat calls for heat and the boiler goes on, the water temp in the boiler doesn't have to reach 212 degrees to start boiling. It boils at a much lower temp (say around 130 degrees), thus generating steam much quicker for the next heating cycle. Both reasons are a savings dollar wise. Those are the two main reasons that I want to maintain the vacuum portion of the system. Like I said earlier, if I can't get the vacuum valves, I'd like to try to convert a regular steam vent to a vacuum vent by sweating a check valve onto the outlet of a regular radiator steam vent. Any suggestions? Thanks, Ted B.

Steamhead

Vacuum

"All the steam is drawn back into the boiler"? I'd say you have a basic problem there. All your steam pipes should be insulated with at least 1-inch of fiberglass- including the header and equalizer. You can get tubular insulation made to fit around your pipes from most supply houses. The less the steam condenses in the piping, the less vacuum you'll get. There will still be some vacuum generated in the radiators as the steam condenses there, but if your piping is well insulated it will continue to draw steam from the boiler after the burner shuts off.

There's more to a vacuum vent than a check-valve on the outlet. Dan's "The Lost Art of Steam Heating Companion" has a cutaway view of one. I wouldn't put a check on the inlet to a standard vent as water will accumulate in the vent and not be able to drain due to the closed check. This would cause the vent to spit and might ruin it.

As a temporary solution, try boiling your malfunctioning vacuum vents in vinegar. This may get them working again.

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Ted Burzynski

Vacuum Vent Valves for Steam Radiators

Thanks for the tips. I'll try the viniger bath on the malfuntioning valves and I'll get the main header pipe insulated. The insulation was taken off of the header some years ago because it was the old asbestos impregnated paper type. As far as adapting a check valve to regular steam vents, I was talking about attaching it to the outlet side of the steam vents, not the input side. Okay, thanks again for the tips. I now have a couple of things to try. After I've tried them, I'll post my feedback on the WALL. Ted B.