Vent Siziing Help

Steamhead (in transit)

The way to do this is to calc the amount of air in each sub-main, then divide the air in the 2-inch main by the number of sub-mains running off that main. Size your sub-main vents by adding the fraction of the air in the main to the air in the sub-main.


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Bob_43

Vent Sizing Help

Good Morning.

I need help sizing Gorton Main vents for my in-laws house. Two inch pipe going out, 1 inch pipe coming back. Main vent at end of 1 inch pipe before it drops back to Boiler.

Main # 1 - 32 Feet(32 Feet of 2 Inch, 32 Feet of 1 Inch) 64 Total.

Main # 2 - 24 Feet(24 Feet of 2 Inch, 24 Feet of 1 Inch) 48 Total.

Main # 3 - 40 Feet(40 Feet of 2 Inch, 40 Feet of 1 Inch) 80 Total.

Thanks,
Bob

Steamhead (in transit)

Here's what I'd do

Main 1- three vents total: two Gorton #1 and 1 Hoffman #4A;

Main 2- 2 Gorton #1;

Main 3- 1 Gorton #2.

Then stand back and watch how well it works.

If the mains and dry returns (the 1-inch pipes) are not insulated, this would be a good time to do that too.

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Bob_43

Thanks Steamhead. The mains are insulated, but the vents are old, clogged, and undersized.

Bob

Boston_2

Venting - Wet and Dry

While we are on the subject of proper venting I have a question that pertains venting wet returns and dry returns.

My single pipe main is setup in the following fashion. I have two 2” mains that head off in opposite directions from the boiler (Bullhead Tee). The main that heads left goes 3 feet and breaks into two smaller mains ( 1 1/2”) that again head in different directions (each main, branches off and heads directly to the radiators on either the 1st or 2nd floor). The main that heads to the right, goes 15ft and again braches off into several 1 ½ “ mains that go directly to either the 1st or 2nd floor radiators. Just before the 1 ½” mains head up toward the radiator there is a Tee at the bottom for the 1” returns, which start off as dry returns and then all connect into two wet returns (on opposite ends of the basement) as they head underground and back to the boiler.

The way that I have seen steam vented is similar to the way bob c. described, at the end of the dry returns just before the boiler. Since all my returns end up becoming wet returns and connect together at different places, where’s the best place to vent? At the end of each main? Which technically would be 7 main vents since there is a branch for each radiator? I currently only have one vent at the end of the 15 ft section of the main.

Steamhead (in transit)

Let us know

how well you make out!

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