Main vent help in Atlanta

madley

Greetings from Atlanta!



I'm having some problems with venting (and venting noise) on my system in a circa 1920 house.



The system is a one-pipe two-main setup steamed by an American Radiator Red Flash #1 that was converted to gas at some point. While the actual steam generation portion of the system seems to work just fine, I've got some system balancing that needs to take place.



During and after the steam cycle I'm getting loud air/hissing from my rad vents. To combat this, I've replaced all the vents (Hoffman #40's) and dropped the cut-in/differential to something a little more sane. However, it appears that I'm either not main-vented or what 'may' be the main vent is clogged (thus forcing all the air in the mains out the rad vents).



I've attached a picture (1) of when the main lines making the transition to wet, the question I have is are the top caps some old-version of a main-line vent or some other mystery contraption? If these are indeed circa-1920 main-vents would this still be a good place to install either a Gorton or Hoffman main vent.



Since there doesn't appear to be much professional steam knowledge in Atlanta, I'm hoping someone on this board can point in the right direction to negate the rad venting problems.



Thanks!

BobC

venting

That is one ugly main vent!



Is that vent threaded into a 3/4" fitting? Measure the diameter of the main and it's length so we can tell what kind of venting you should have. he pressure should be no higher then 1.5PSI and your larger radiators may need more aggressive venting tan Hoffman 1A's.



At least your not dealing with the 14F we had in Boston this morning.



Bob

madley

measurements

Hey BobC -



It's a 2.5 inch main. The pipes leading to the vents in picture #1 are 1.5 inch (you can see the main lines in picture #2). The vent diameter is 3/4 inch. The vent appears to be similar to a Hoffman #4 (hard to tell w/ all the rust and gunk from years of neglect).



I have ~41 ft on the 1st main and ~80 ft on the 2nd main.



Would the location in picture #1 suffice for the time being, or should I consider relocating the vents to a more suitable location (12 - 15 inches before the end of the 2.5 hits the 1.5 to go the wet-return) day one?



Thanks for your help, it's greatly appreciated!

crash2009

The main vents

in your 1st picture are constructed just like mine.  We put the new ones up on an antler like this.  The antler is supposed to simulate the vent being back 15" from the drop.  We did this last year, just to get through the winter.  When we re-piped this summer we used the same contraption on the new pipes and put it back 15"

BobC

Venting for mains

Sorry it took me a while ton get back here but if that main is 2.5" ID (2.87" OD) then you have 1.4 cu ft of air in the short main and 2.8 cu ft in the long main. That means you should have a Gorton # 2 on the short main and 2 Gorton #2's on the long main.



Just to be clear I'm including this data for a 2" pipe. If the OD on that main is 2.37 then it is a 2" ID and you have 0.87 cu ft in the short main and 1.74 cu ft in the long main. That indicates 2ea Gorton #1's (or 1ea Hoffman 75) for the short main and 1ea Gorton #2 for the long main.



That old piping is not going to take a lot of abuse and could be a bear to get apart. The better part of valor might be to setup a system like crash has to get that vent back from the end of the main, that would be a lot easier. December is not a good time to play with the pipes if you don't have to. Just make sure the new pipe slopes a bit so any water will flow back to the boiler. Also be aware that Gorton #2's are pretty big. so make sure you have room for them.



Bob