1-pipe system; 2-pipe rad; 1-air-valve

jpf321

So a friend of mine just moved into a new place .. with a Bryant Mfg. 9-443 boiler (I'll leave you to look that one up ;-) )

Anyhow, besides the fact that several of the radiators include closed-tight Hydronic "bleed valves" instead of air-vents ... (knuckleheads) .. they have a few very loooong old rads (about 10-12ft long) that have floor inlet valve on *both* ends and it seems, only 1 air-valve (at *one* end) .. no traps (fyi)

Unfortunately, these old gals are also within "built-in" rad covers so I can't see the middle bits very clearly, but I can only presume that it is a straight-through rad and not 2 rads uncoupled in the middle.

Anyhow, the question, how to vent? ... (I don't have my TLAOSH nearby, perhaps this is a known Dead Men problem)
Should there be a vent at each end?
Should I close 1 floor inlet (opposite the vent at the current end)?
Should I double-maximize the venting?
I presume that as the steam moves through the main, the steam enters the near end of the rad, and the rad begins to consume and condense (nd allow air to escape the far end down-riser(?) .. then the steam continues down the main and enters the main on the other end and now the rad is consuming and condensing on from both ends, and both risers are now supporting condensate and steam and no place for the air to escape .. so now there's an air bubble in the rad and no escape (except for a closed hydronic bleed valve) .. and if I were to replace with a regular steam vent, it would only be vented on 1 end, and presumable close very quickly due to steam entry very close (6inches away) .. You see my problem? The perfect place to vent would be in the rad middle .. but I don't have access and if I did have access, I don't thnk there are vent ports in the center .. hmmm ..

Anyhow .. I'm sure this house will present other head-scratchers ... happy to hear your thoughts.

jpf

KC_Jones

Those sound like 2 pipe air vent rads, being that long, to me this makes sense. The steam should enter from the end opposite the air vent and the condensate exits on the vent end. The pipe on the vent end should be ~1 pipe size smaller, this helps encourage the steam to enter the supply end of the radiator.

jpf321

Thanks KCJ -- Yes, I do believe that there is a pipe size difference on the two ends. Are these specifically included in TLAOSH? Page reference? Otherwise, I'll hit the old Billy Baldwin books.google.com

jpf321

In Mills' chapter XIX .. every rad is shown as 2-pipe with none with Air Valves (IIRC, Hoffman and Gorton didn't patent until about 1902, Mills penned this in 1890). I absolutely LOVE the pictures in the old books.

https://books.google.com/books?id=bWMJAAAAIAAJ&printsec=frontcover&dq=John+Mills+steam&hl=en&sa=X&ved=0ahUKEwj70svL1oThAhWRzlkKHWJSBhQQ6AEINDAC#v=onepage&q=John Mills steam&f=false

Gorton History : https://www.gorton-valves.com/proud_history
Hoffman born in 1905 (scroll to ITT) : https://www.pmmag.com/articles/91715-greatest-plumbing-heating-inventions

KC_Jones

jpf321 said:

Thanks KCJ -- Yes, I do believe that there is a pipe size difference on the two ends. Are these specifically included in TLAOSH? Page reference? Otherwise, I'll hit the old Billy Baldwin books.google.com

I don't have my copy in front of me, but yes there is information about the 2 pipe air vent systems, that's how I know about them.

JUGHNE

Does the outlet side go down and have a water seal that dips below the water line? That would keep the steam from entering from the return side.

jpf321

Judging from a few other exposed pipes in the basement, it did look like they dripped a few other rads .. so my assumption that this is also dripped (although the pipes lie hidden behind shiny clean sheetrock)

Thanks for everyone's help. I put on a new Gorton D and she's heating up nicely. Although I do think the vent need to be on the opposite (small pipe "dripped") end. I'll check the tappings .

jpf