Main vent location

Circa1902

First winter in this house. I've been learning about steam heat and this system has multiple issues. Trying to address them, one at at time. Right now, I'm insulating pipes, easy fix.

My first question is about the main vents (one pipe system) - this system does not have any main vents. So, I'm looking to get them installed but have a question about where specifically on the main they should go. I keep hearing "at the end of the main." Can I add the main vent towards the end of the main, but still before some of the radiator branches?

The reason for this is, i have a main that makes a U-turn at the end of the main and then a return which basically follows the same route as the main, bringing condensate back to the boiler. However, at the "U" there are a bunch of elbows and fittings in addition to the individual radiator branches, and I'm not sure if there's enough space to install a riser with a main vent/antler. (vertical space not an issue). So can I have the main installed right before all this?

Two pics in my dropbox, one is "front" and one is "back." I've labeled everything. Where would you suggest putting the main vent? I was thinking put it towards the end of the main, on the side of the brick wall shown in "back"? This would be upstream from the three radiator branches, but would still minimize the amount of air needed to be pushed through the radiator air vent?

https://www.dropbox.com/s/o86dbcv0r23s1nd/front.jpg?dl=0

https://www.dropbox.com/s/8i8uzhnjmmjrvky/back.jpg?dl=0

Thanks!!

Fred

Put your vent anywhere on that return that goes back to the boiler. The goal is to vent all the air out from a location after the last radiator run-out and that "return" is still technically the "Main" on a one pipe parallel flow system.

New England SteamWorks

Like Fred said. Anywhere between the brick wall and the boiler if there are no further radiator take-offs. Once upon a time you had them. Usually they were right at the 90 elbow where the return drops down at the boiler. Often times someone replaces the vertical drop down to the boiler with copper, and when they do so they also get rid of the vent tee. Makes no sense, I know, but quite common. That might be your best spot, though usually we like to put them back 18" or so from the drop. Send a picture of this piping, lets see what you have there.

Circa1902

New England SteamWorks said:

Like Fred said. Anywhere between the brick wall and the boiler if there are no further radiator take-offs. Once upon a time you had them. Usually they were right at the 90 elbow where the return drops down at the boiler. Often times someone replaces the vertical drop down to the boiler with copper, and when they do so they also get rid of the vent tee. Makes no sense, I know, but quite common. That might be your best spot, though usually we like to put them back 18" or so from the drop. Send a picture of this piping, lets see what you have there.

Thanks guys! I'm glad my photos (and description) made enough sense.

So this part that you said (bold) made me think - I have something like that, but it's... strange, not sure exactly what to make of it. I haven't given them much thought:


https://www.dropbox.com/s/avzr52mp7ouwuzo/IMG_2518.jpg?dl=0

https://www.dropbox.com/s/v96hdy3fdajg0mz/IMG_2517.jpg?dl=0

https://www.dropbox.com/s/p75hlj63q60h9sx/IMG_2520.jpg?dl=0

https://www.dropbox.com/s/e0m0zom944n0krn/IMG_2521.jpg?dl=0

I have two mains, and those two vents are each in the location you describe - at the 90 elbow before it drops down. Now, I had initially taken one look at them and thought "those couldn't be the mains, they're much too small." They look like old radiator vents. One says Syphon King 102, the other says Dole 1A Vari-vent. I had initially assumed they were air valves of some sort to let air into the return, and prevent a partial vacuum effect. (Haven't given it much thought honestly. They were just way too small to be mains.)

Now that I take a closer look, does it look like it could be the T is actually a 1/2" and the valve is on a reducer??

The valves, for what it's worth, seem to be completely non-functional, I do not believe they're venting air at all.

Leon82

It looks like there is a reducer bushing in there . One looks pretty rough so get some pb blaster or similar before you try to remove it.

Circa1902

Will definitely let the PB blaster soak in before i try to remove it!

If this is the right location for the mains... I'll have to run by a schematic past you guys to ensure i'm installing the mains right. Based on what I've read, I probably need two Gorton 2's on one main, and a single Gorton 2 on the other. But that's probably a post for another thread.

BobC

That location can be used, it would be best to remove the vent and the reducing bushing,

Then install a short nipple a 90 facing up and a nipple that gets you well above that return, then a coupling and a vent. Is that bushing a 3/4 or 1/2"? Also how long are the mains and about what size pipe?

Bob

Fred

Those are where the original vent were, and those were the main vents. They are way too small to vent the mains. They might have done the job when the original coal boiler was there. Coal boilers literally ran the entire winter and the water just simmered. Because they ran as long as they were fed coal, once the air was out of the system, that was it until the boiler ran out of coal or Spring, whichever came first.
That's not an ideal location. It would be much better if the vents could be above the horizontal, before it turns down. If you have to use that location, take those reducing bushings out of the Tee and put a full size elbow in there and a long nipple to take it up above the horizontal as high as you can go, then put a coupling on the end of the nipple and install your new vents. Depending on the length and diameter of your mains, Gorton #2's or better yet Barnes and Jones Big Mouth vents are what you want. Those old vents are a joke for today's gas or oil fired boilers, even if they worked.

Circa1902

Both mains are 2" pipe i believe, one is 36' and the other is 18'.

Fred

Like you said, two Gorton #2's on the long one and one Gorton #2 on the short one. The two Gorton #2's can be mounted on the same vertical vent pipe you install, just use a Tee at the top and a couple elbows to make an antler.

Circa1902

Fred said:

That's not an ideal location. It would be much better if the vents could be above the horizontal, before it turns down.

I may have to use that location initially at least, and move it to a more ideal location in the offseason. (I also have copper as near-boiler piping so... my list of fixes is long and I need to prioritize).

For my education, can you explain why above the horizontal is a more ideal installation location?

Fred

You want to keep water and dirt from washing into the vents. Water will prevent them from venting and dirt may prevent them from fully closing when steam hit them.

New England SteamWorks

They are non-functional. Tapping too small even if they did work. Do this:



All better!

Even better, and if you're feeling ambitious, I bet the vertical drop(s) with the vent(s) that goes down below the waterline has no way to be flushed out. Sooner or later that will cause problems. It will gunk up and slow or block the return of the condensate. So if you are going to disassemble, you could go whole hog and start down there and install some drains so you can flush in the future. Of course, you might want to wait until after football season...

Circa1902

Thank you all for your help. My goal for this heating season is to get it functional and as efficient as possible to get us through the winter, (insulating pipes, fixing mains, balancing the system) and then make functional and ideal upgrades as necessary in the offseason.

New England SteamWorks

You'll find new main venting to be a radical improvement over your current set up.

steamhouse

> @New England SteamWorks said:
> You'll find new main venting to be a radical improvement over your current set up. What is the strainer you mentioned? What do they look like? Thanks

New England SteamWorks

Strainer small investment to protect your Big Mouth(s):

Danny Scully

If those tees are 1/2”, I think this is a good alternative to your typical 15” back from end of main location. I’ve seen many a dead men utilize this. As long as it’s above the “A” dimension, I would feel confident in its performance. If you can get back to the 1/2”, install a nipple and tee with a plug (for cleaning/inspection). Then, extent a nipple vertically up to your main vent(s). When it’s piped off the horizontal drop to the wet return you don’t have the same effect as steam/condensate hitting the last elbow and pushing up into the vent. Personally, i think it’s a better location then right at the end of the main.

Circa1902

And I want those vents as high up as possible right?

Fred

Circa1902 said:

And I want those vents as high up as possible right?

Right