Worth fixing/keeping a single pipe vacuum system?

Steamhead (in transit)

change the rest of the rads to Paul vents and hook them up.

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ChasMan

Worth fixing/keeping a single pipe vacuum system?

I can't imagine there are too many single pipe vacuum systems still out there, and I have no idea whether it would be worth trying to fix the thing or just discarding it.

Here's the deal: The building is six stories, and originally utilized what I would guess is a Paul system. If I had to guess, I would say about 80% of the radiators still have the air line running to them. The vacuum pump is still present, and works. It will not, however, pull a vacuum. I would assume this is because of the many air vents that have been installed over the years and leaks that have developed. When the pump is activated, it does, however, at least pump water, and spits out a pretty good amount of it after a boiler cycle where the vacuum pump was not turned on. I would assume the water indicates that some or many of the steam traps are not working properly, correct?

Would there be any efficiency or other benefits to be gained by keeping this system and trying to fix it (I was shocked to find you can still get the traps!) instead of just scrapping it in favor of adjustable radiator vents? It seems like that would offer better heat control to the floors.

I am guessing that there are no main vents in this things due to the vacuum design, and that a half-broken vacuum system is far worse than no vacuum system at all? My other fear is that piping sizes and the whole mess was based around the idea that the system would be under vacuum, and that there may not be an easy fix ...

Any insight would be appreciated.

Steamhead (in transit)

Fix it!!!

the fuel savings were about 35% when the Paul system was retrofitted to existing one-pipe steam systems.

My guess is there are a bunch of open vacuum lines where ordinary one-pipe vents were installed. Cap these, then try the pump again. It will probably work.

To vent the steam mains, you can use ordinary radiator traps hooked up to the vac pump.

Let us know how you make out!!!

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Kool Rod

Even if the removed air lines are capped, won't any normal vents defeat on individual radiators defeat the whole system? Unless I'm not understanding how it works, it seems like even one vent to atmosphere would "de-vacuum" the whole thing.

Erich_3

Paul Air Vents / Where Are You Located?

Where are you located? You may be near one of the many steam experts. In the world of steam there is nothing better than a properly operating vacuum system. Here is a link to new "Paul" air vents.

https://www.statesupply.com/displayCategory.do?Id=1807

Robert O'Brien

We're in Michigan. I found those "new" vents online, and I also found a huge stash of used vents down in the basement, most of which pass the "blow in it" test, although whether they close on steam is another question. At $90 a pop, it's worth testing though!

My only gripe with this system is the potential inability to control venting rates. From going through the old catalogs, it looks like, at one point, the Hoffman #3 had an internal screw that could be adjusted to control venting ( http://www.heatinghelp.com/pdfs/5.pdf ), while at other points in time, it did not ( http://www.heatinghelp.com/pdfs/310.pdf ).

It seems to me, that even if the system pulls a vacuum, it will still suffer (in theory) the same issues that steam systems suffered after the initial transition to gas/oil -- the same size vent on the whole system works badly with an on/off fired heatsource.

On the plus side, the system can't leak too badly. It's holding six pounds of steam right now pretty well. It's painful to see an old Vaporstat manual hanging on the wall, and a Cut *IN* on the boiler right now set at 4 pounds on a 2 pound differential.

Anyone know if there is still a source for Hoffman #2s, or any other vacuum valve, in the event that there are rads where re-attaching the air line is not practical?

ttekushan_3

pulling a vacuum

seems to iron out large differences in radiator heating time. For example, uneven two pipe systems where vacuum is reapplied even out pretty well. The same should hold true for any system. Besides, restoring it to its original design integrity rarely creates problems; on the contrary, the balance problems likely began when the vacuum was deactivated.

-Terry