Do you vent branches off your main?

adamfre

I have two 2" mains that travel the length of my house (on opposite sides). This was put in way before main vents were a thing, so I currently have no main venting. I'm pretty sure I'm going to put a Big Mouth on the end of each of the 2" mains, but I've also got two 10' branches that hang off one of my mains, one feeding about 108 EDR, the other 70. The larger EDR loaded branch is 2" dia, the smaller one is 1.5". Would something along the line of a Gorton #1 be appropriate on the end of these branches, or is 10' just not long enough to worry about?

Fred

If you don't vent those branches, the air in them will have to be pushed through and out the radiators attached to those branches. That will prevent you from getting all the rads hot, at the same time, but not the end of the world. A Gorton 1 is probably sufficient but you may want to look at the Barnes and Jones Vari-Vent, also available from Amazon. A lot more venting capacity than the Gorton 1 and adjustable so that you can fine tune the steam distribution in those branches, relative to the longer mains.

Steamhead

If you're not sure, try it with just the new main vents. If the branches are still slow, add vents there too.

adamfre

Thanks!

Jamie Hall

You don't mention whether it is one pipe or two pipe. Makes a difference. If it is two pipe, you also must place vents on the dry return(s)!

adamfre

Sorry I didn't mention it @Jamie Hall . It's an old 2 pipe, air vent system, with wet returns.