Adding main vents to a "two pipe" air vent system.

grantsweatshirt

Credit to @EdTheHeaterMan for pointing this one out. After further investigation it would appear that at one time my building used the "paul" system. Now all that remains are the air lines, some capped, some cut off. I think converting back is out of the question as the only place I noticed the air lines was the 1st and 2nd floor. My building now essentially operates as a one pipe with a drain or two pipe air vent system. Timestamp 22:10 of the video. or pg. 228 (figure 2) of TLAOSH shows you an idea of my set up.

I'd like to add main venting, my mains do not have any. I'm unsure of where to add these vents. Two of my 3 mains run above the drop ceiling in 2 seperate apartments. I'll attach a picture of what the end of the mains look like in those apartments.

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For staters, we'll call this Main 1. The main continues a few more feet to the left through the wall to another radiator. See pic, that is the end of the main.

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I'll begin by measuring the lengths of the mains and the diameter of the pipe. From what I can tell it looks like it begins as 4.5" or 5" pipe before it necks down at the end of the run to 2.5." Is there any other information I should gather, so you experts can better guide me? Thanks in advance.

https://www.youtube.com/watch?v=tpA1epqFMCw&t=1386s

EdTheHeaterMan

You can find information about the proper main vent location on line however you may not find that you have a tee fitting at that ideal location. so you might try this.

• The ideal location is about 15" before the last elbow on the main, just before it drops into the wet return. In your case that would be the last elbow before the last radiator.
• Since there is no fitting at that location you can just drill a hole in the 2" pipe main. I do not recommend a hole large enough for 1/2" pipe on a 2" steel pipe because the threads are too course, 3/8" pipe threads are somewhat finer and a 3/8 close pipe nipple will not restrict air flow that much. then you can use a bushing to increase to 1/2" with a bushing .

You should have the vents about 10" above the bottom of the main, so a 1/2 x 8" pipe nipple should do fine. You may need to take a ceiling tile above the vent location to accommodate that vent.

Other steam experts may have a better idea, but this is what I would do in your case.

Pumpguy

In Dan's TLAOSH, he suggests converting a one pipe system to a Paul air line system for the benefit of mechanical air removal vs using steam pressure. Your existing piping arrangement, and the fact that 2/3 of the needed air line piping is already there, make this less difficult than starting from scratch.

The way your system is already set up, the vacuum pump itself is very easy to accomplish. You would need to add the Paul valves to the radiators, run the rest of the air lines, then connect them to the Paul valves and vacuum pump. PM me for more information if you'd like details.

Now, how cost effective this would be, and how much an improvement to the heating this re-conversion might be, I can't really say, but others might.

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1815520#Comment_1815520

Is that really a true recommendation? Or is that something the Dead Men did back in the day? I believe that Dan mentions in a seminar that the Dakota in NYC was actually converted from a Paul system to a two pipe with radiator vent system so get it to operate today. (not the other way around)

Steamhead

I wonder if that was a situation where the exhauster went bad and they didn't want to spend the money on a vac pump? @DanHolohan ?

HeatingHelp.com

@EdTheHeaterMan, here's the story about the Paul system and the two-pipe, air-vent system:

https://heatinghelp.com/news-and-media/dead-men-tales/the-paul-system-and-other-delightful-discoveries/

And here's the story about the Dakota:

https://heatinghelp.com/news-and-media/dead-men-tales/heating-john-lennons-apartment/

It's also mentioned here around minute 32.

https://youtu.be/U07Mp5DeFX4?si=Sv5Z4ts1UxlsPAK3

Pumpguy

@EdTheHeaterMan, Dan's comments about converting a one pipe system to a Paul system are found in TLAOSH, page 251, where he writes:

"I often wonder why we don't use Paul's ideas as a retrofit for today's older one-pipe systems. The fuel-savings documented in the old days were nearly 35 percent when the system was added to a one-pipe.

The physics haven't changed, the equipment is still available, as is the know-how. So how come we don't use the Paul System as a retrofit on one-pipe systems?

Something to think about, eh?"

As I posted earlier, the OP is already half way there now.

EdTheHeaterMan

So all the OP requires to save up to 35% on operating costs is someone to add a vacuum pump and connect Paul air vents to all the radiators (still available) and some rolls of copper tubing to go from each radiator to the basement vacuum pump. Are you interested @Pumpguy? I will help with supervising and design, from my wheel chair

🤣🤣🤣🤣🤣

Pumpguy

I can supply the vacuum pump and instructions how to install it. The rest I leave to others.

While I make no claims about fuel saving or operating efficiency, I have no reason to doubt these earlier reports.

grantsweatshirt

@EdTheHeaterMan many thanks! This is the exact info I was looking for, I'm still working on measuring the sizes and lengths of the mains as time allows for me. Hopefully once that info is aquired you could also provide some insight on what size vents I should install or tag someone with that knowledge.

@Pumpguy the building I operate is 4 stories. there only appears to be remnants of the "paul system" on the 1st and 2nd floor. Reviving that system sounds enticing with the supposed savings/efficiency and all, but being so late in the year I don't think thats a project I want to get started on. Once I get this main venting sorted I'll PM you, perhaps we could start discussing some changes for next season. Thanks for the help.

grantsweatshirt

delcrossv

https://forum.heatinghelp.com/discussion/comment/1815586#Comment_1815586

If you move forward on it, share it here.

grantsweatshirt

@delcrossv will do.

can anyone advise, when I measure this main pipe using a flexible tape im getting a circumference reading of roughly 10.125.'' when i divide that by 3.14~ i get 3.2245~ which doesnt match to anything on a size chart. Do you round and just call it 3'' pipe? Also when measuring circumference around insulation (asbestos) is subtracting an inch enough? Thanks.

ethicalpaul

no, it’s probably not enough, but we don’t know how thick it is, so we can’t know. Measure the uninsulated pipe.

The nominal size of the pipe is the inside diameter as should be indicated on the charts

grantsweatshirt

@ethicalpaul 10.125" is the circumference measurement of the uninsulated pipe.

ethicalpaul

then my best guess would be 3”. Look at the elbows and tees. They usually have the size stamped on them