Main vent placement on \"counterflow\" main?

Paul Fredricks_9

Hi Jason,

I've seen this type of system before. Just realize that the condensate has to come back in the same pipes that the steam travels in, but in the opposite direction. Too much venting may hold the condensate back, causing it to go up into the radiators. This would depend on how much steam you are producing and the size of your mains. Experimentation is the way to go. Worse comes to worse, you may have to go back to the single #2.

Jason_44

I have one continuous main that feeds all the radiators in the house (1-pipe steam). I've been told this is called a "counterflow" system. The main leaves the boiler, loops around the basement, and comes right back to the boiler.

There is a single main vent, about right smack in the middle of the loop. Is this the right place for this vent? I know that normally, a main vent is located near the end of a main. However, my main has no "end" to speak of.

Jason

Steamhead (in transit)

Well, Jason

I'd call that a counterflow loop system. Tthe vent location is at the furthest part of the main from the boiler, and as long as the Gorton #2 vents get all the air out quickly you should be fine.

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nicholas bonham-carter

counterflow?

counterflows that i have seen pictured slope up as they extend further from the boiler until thy end after the last radiator take-off with a vent at that point.

parallel flow systems start out high above the boiler, and are pitched down, as they extend throughout the area they serve; until they finally drop down to the floor, as the wet return, with their vent just before they drop. a cup of water poured into the steam main above the boiler should run out into the wet return.

it's always better to have the vent as close to the end as possible[but protected from water-hammer]. this reduces the volume of air in the system, even beyond the last radiator take-off. air is more unpredictable than steam as far as expansion etc. as it is heating up. if there is any way to put a vent on its usual place it would be well worth the effort. maybe a hole could be drilled and tapped. the gorton # 2 only needs 1/2 in.--nbc

Jason_44

Yep, that's where mine is.

I've got a second Gorton #2 on order. I decided to try one to start with (mostly cuz they're so damned expensive), and things are definitely quieter upstairs. The radiators are heating up faster, too.

I'd say I've already cut the hissing noise from the radiator vents in half just with the single Gorton #2. I imagine a second #2 will make things even quieter.

Jason

Jason_44

Mine starts up high away from the boiler (near the basement ceiling) and loops around the basement back to the boiler, several inches lower than where it started.

Jason

nicholas bonham-carter

maybe not counterflow

as long as it works, fine. this does seem to be a parallel flow piping arrangement, and although not in your case, would usually have the main vent at the end of the dry return, before it drops down to the boiler.

one reason to have it so far to the end, is that the remaining air which has not been removed, can become a "wild card". when the burning stops and the vacuum develops. this remaining air then expands and tries to move to the vent, against the direction of condensate flow. if you have no problems, then it can remain as it is. if you have irregular condensate flow at the end then it would be wise to move the vent to its usual location.--nbc

Jason_44

Yep. I figured it's short money to just play around with it a little and see what happens.

Next on my list is to put TRV's on the rest of the radiators to balance things out a bit.

Jason