Venting Mains

bconstant

I know this has been covered a thousand times on these boards, so hopefully you have patience for one more.

I have two mains that T off from the boiler, one goes to the front of the house, one to the back. Neither are properly vented - and it doesn't look like they were ever properly vented even way back when, and you'll see why I think that by looking at these photos:

Back:

This Gorton wasn't venting - it was plugged up, I replaced it with a new Gorton straight D.

Front:

This is a Matco-Norca AVA-125 that has been completely painted over, and the last time the basement was painted was probably 2002 or so. I've replaced this with a Gorton angle D.

This is what the new one looks like:

If I took that stem off (is that possible/advisable?), I could put a straight D on it - there's enough room between the pipe and the ceiling.

I'd like to replace both of these with #1's or #2's, but the pipe isn't drilled for that and this rear pipe has this goofy stem on it - not sure if it serves an important purpose or not.

At the very least these are now both venting much better than before, but in order to do it "right" will I have to chop out these sections of pipe and replace them in order to get bigger vents?

Fred

You do need much more venting on those Mains. In the first pircture, it looks like that's a large bushing in that pipe that can be removed and a bushing with a 1/2 or 3/4" opening installed. On the second one, the pipe nipple sticking up looks like a 1/2" nipple and Tee. You should be able to install a couple Gorton 2's or several Gorton 1's on an antler off of that Tee.

KC_Jones

I am pretty sure that is 1/8" pipe in the second pic because that is a radiator vent connected to it. Same thing on that one remove the bushing in favor or a 1/2 or even 3/4 bushing to add more venting. How long and what size are your mains?

Abracadabra

+1 for removing the existing bushings and installing bushings that reduce to 3/4". Torch and wrenches or a jigsaw/sawzall with metal/carbide blade and a chisel. Pick your medicine.

bconstant

Abracadabra said:

+1 for removing the existing bushings and installing bushings that reduce to 3/4". Torch and wrenches or a jigsaw/sawzall with metal/carbide blade and a chisel. Pick your medicine.

Ok, this might be a job for a proper handy man, then.

KC_Jones said:

I am pretty sure that is 1/8" pipe in the second pic because that is a radiator vent connected to it. Same thing on that one remove the bushing in favor or a 1/2 or even 3/4 bushing to add more venting. How long and what size are your mains?

Yeah that thing is definitely 1/8".



The main starts here in this picture at the top nearest the ceiling and runs for 8 feet before hitting the T, where it then runs 22 feet to the new Gorton D I installed, and 25 feat to that angle radiator valve I installed at the front of the house. After the valves, both mains actually turn downwards towards the floor before disappearing into the wall. I just always assumed that's one of those choices that the Dead Men made that you question at your own peril, as Dan might put it.

I've insulated all the mains I can as well as a few pipes exposed elsewhere in the house (did it as tastefully as I could by covering the insulation with cotton rope), but it's anyone's guess as to how well they did the pipes in the walls.

Steamhead

How long does the steam take to go the distance between the boiler and the vents?

bconstant

Steamhead said:

How long does the steam take to go the distance between the boiler and the vents?

The boiler is a Burnham Independence IN7. Once the thermostat kicks in, the boiler goes through its startup process but I'm not sure at what point it actually starts making steam. I started my stopwatch just after the boiler made its first series of clicks.

3:00 - the Gorton D on the Rear Main audibly hisses.
5:00 - The T in the main (8 ft from boiler) gets too hot to touch.
7:45 - Both mains are hot all the way across, they hit this temp almost simultaneously.
9:00 - Living Room radiator gets steam, 12:15 vent hisses, 20:00 radiator is hot across.

I picked the living room rad just because it's the largest we have (it's a 5 column, 13 section hot water rad running on steam, obviously) and I could only be in one place at one time. This radiator is 2 floors above the boiler.

Steamhead

You might be able to get away with those vents, at least for now. I like to see faster distribution in the steam mains, but am loath to take stuff apart like that when it's this cold. Once in a while you get a bushing that shears off when you try to wrench it, and getting the remains out is no fun on a 5-degree day.

As far as timing, start when the steam enters the 8-foot pipe that starts at the boiler and ends at the T. I'm assuming that adds another 30-60 seconds to the time it took to get from the T to the main vents, which would give a total time of 3:30 to 4:45.

You could probably get down to a distribution time of 60-90 seconds by adding a second Gorton D (or a Gorton #1, they have the same vent opening) to each main. The Gorton #2, my favorite main vent, is so big that it's probably overkill on this system.

bconstant

Steamhead said:

You could probably get down to a distribution time of 60-90 seconds by adding a second Gorton D (or a Gorton #1, they have the same vent opening) to each main. The Gorton #2, my favorite main vent, is so big that it's probably overkill on this system.

If you scroll back up and look at the picture labeled "front", that stem on the front main there, can I remove the nut at the top of that little T on the stem and install a second vent? It would be another 1/8" vent, but given that installing anything bigger will take drilling/wrenching, maybe this would be a quicker solution for at least one side of the main?

Steamhead

You could, but if that small piping is also 1/8", it wouldn't do any good. You need to be able to move enough air thru the pipe to support two vents with 1/8" ports.

bconstant

Steamhead said:

You could, but if that small piping is also 1/8", it wouldn't do any good. You need to be able to move enough air thru the pipe to support two vents with 1/8" ports.

Oh, duh, that's self-evident. Yeah OK I guess I have some work to do come spring-time. Thanks!

bconstant

I did the responsible thing and had my plumbers send a mechanic to do this. It was above my comfort level and while it wasn't cheap (nothing in the city is), it was done cleanly and quickly. He had to use some herculean measures to get anything to turn, and I'm glad it was his problem and not mine. He installed two Gorton 1's (couldn't fit anything bigger due to walls) and it cut the time for the steam to travel the mains by 30%-40%. Definitely worth it!