Main vent sizing?

Matt_28

Hello, I think my main vent pipe sizes are small and would appreciate any help in finding replacements. Currently, my radiator vents are noisy and I am realizing that they are doing most of the work to vent my system. I have 2 mains with Vent-Rite #35's just before the drop to the water line. My main lengths are as follows:

1. 25'x2 with a 9', 8', 8', 15' & 15' branch to radiators (I am unsure of the branch sizes) and a 8'x1.25 return.

2. 35'x2 with a 6', 17', 5', & 13' branch to radiators (I am unsure of the branch sizes) with a 3'x1.25 return


Thanks for any responses and all the help I have had from The Wall in the past.

Matt

Steamhead

That's Easy

Two Gorton #1 or Hoffman #75 vents on the long main, one on the short main. I see this combination all the time and the above sizes work great.

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Matt_28

alternatives?

Is there any one vent that is equal to two Hoffman 75s or Gordon 1s? I am hoping that I will not have to branch off the existing riser to add two vents to the long main.
Thanks for you help Steamhead.

Matt

mpeterfr

main vent sizing

When adding a second main vent what is the correct way to pipe this?

Steamhead

All you need to do

is screw a tee onto the existing vent riser with the run vertical, and screw one vent into the top of the run. Screw a 90-degree street ell into the bull of the tee, with the female end pointing up, and screw the second vent into that.

Simple!

No, I don't know of an intermediate-capacity vent like you mention. This is why we commonly use two vents on some mains.

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