Main venting location Q

SteamedInOhio

Okay… I just got a wild hair regarding vent placement. I need someone to keep me from doing something stupid… or at the very least from wasting my time.

I have a one-pipe steam system with one continuously pitched (starts high ends low) dry main that traces a rectangle roughly (18’x 25’) around the footprint my house. This main has occasional take-offs (risers?) coming off it that connect either directly to single radiators or in one case to multiple radiators on the upper floors.

One of these take-offs branches out from roughly the middle of the main to a location that no longer has a radiator. The end of this branch is capped off under the floor. I have about 12-14 in. of clearance under there and I was thinking… what a convenient spot for a vent? Assuming all went according to plan it would only take 15 minutes to remove plug add a nipple, reducer, and vent.

Attached is a PDF that shows a rough layout of my piping and the proposed vent location.

My question: Is this a good idea?

Thanks.

Brad White_203

Your end of the run

location will always be the best and will get all of the air out past the point of your last radiator branch.

However, it will do no harm to put a vent in the location you describe, supplemental to the end-of-main vents. It will speed things up a bit, especially to that point.

But I would not make that your only venting location, no sir.

SteamedInOhio

I had no intentions of changing my end of the line venting. I would just be adding the supplimental vent to the open location.

I guess is wasn't sure if there would be any negative effects related to having a vent in the middle of the main.

So much to learn.

Thanks.

Brad White_203

I just had to be sure...

I know it will help so it is an opportunity. Just another location to check now and again. No harm in trying, so see the difference and report back? All systems are different.