Main Steam Vent Location

Steve Garson

After reading about the importance of good venting for steam, I noticed that my system has two vents. They are on opposite sides of the basement, connected to the wet return just before it drops down from the ceiling to the floor. One vent nearly touches the ceiling, so I doubt it has been replaced in ages.

Are these the right locations? Is it sensible to simply replace them, or is there an easy way to test them? My heating works pretty well, but a few radiators don't get real hot unless it is very cold out. The vents on the radiators are in good shape.

Steamhead

That's the \"dry return\"

since it's above the boiler's waterline.

If "a few radiators don't get real hot unless it is very cold out" and these rads are toward the ends of the mains, you likely have a main vent problem. Measure the length and diameter of each steam main and tell us what vent is on it. Outside diameter is fine, subtract 1/4-inch from that to get pipe size. If there's old insulation on the pipes, don't disturb it- measure its outside diameter and subtract 2-1/4 inches.

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Steve Garson

The main steam lines measure OD of 2-3/8", so I guess they are 2-1/8" pipes. There are two main lines, each 41 feet long.

One dry return has an air vent right above the boiler that is a #85 Ventrite.

The other dry return as a #5 Dolem (hard to read upside down and backwards with mirror) located about fifteen feet from the boiler.

Steamhead

That should be 2-inch pipe

Use 2 Gorton #1 or Hoffman #75 vents on each main. You can pipe two vents onto one riser with a tee, as shown in the photo.

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Steve Garson

If I mount two vents on one riser, that means I can just leave one of the old ones where it is, or remove and put a plug in?

Steamhead

No, remove both old vents

and install two Gorton #1 vents on each of the existing risers.

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Steve Garson

What I don't understand is why the vents are so close to the boiler. It seems like they would work better being far away. Can you explain?

Steve Garson

I checked prices and the gorton #1 is $23.64 and the Hoffman #75 is $74. If I buy four, that's $95 versus $296. Do I have something wrong here?

What I am doing is taking your advice and seeing if I can make my present steam system work better; since I am seriously considering a change to water in the summer, using the same thin tube radiators.

I have really learned a great deal from your posts. Thanks!

michael_15

no; those prices are right

Those prices are not outside the realm of expectation. The Hoffmans do in fact cost a lot more.

You could probably get both of them cheaper elsewhere, however. I believe Gorton #1's usually retail around $15-$18; my local supply house has the Hoffmans for around $63, as well.

-Michael

Steve Garson

Just went to my supply house. The only sell Vent-Rites. They sold me four #35.

I hope these are an OK substitute?

Steamhead

Too Small

They're about equal to a Hoffman #4A. Gorton's site is www.gorton-valves.com. Get in touch with Ken Kunz and tell him I sent you. He will see that you get them.

I prefer to locate main vents at the ends of the steam mains, but if the dry returns aren't too long their present location won't affect performance that much.

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