My Shiny Old Toy

mcsteamy

It's been awhile since I had a house with a proper single pipe steam system to play with, but we finally closed on the new place about a half a year ago, and here we go again...



280,000 BTU input Weil-McClain circa 1982.  So far, I haven't done a thing to any of it other than fill it up, fire it up, and replace a few vents.  It works, miraculously.  The header is literally piped tight to the top of the boiler.  Hartford loop?  Aw, heck no.  Working main vents?  Forget that. 



The first order of business is to get the mains vented.  Vents are all back at the boiler at ends of dry returns.  I ordered three Barnes and Jones 134A radiator traps which I plan to install upside down where the main vents otherwise would be.  Looking at the venting charts, this seemed like a good (and cheap via Ebay) way to vent, and I don't see why they wouldn't work upside down, which should allow any escaped condensate to drain back through the vent, while also allowing for installation of a valve to throttle back a vent if some balancing is needed.  Anyone  see any problems with any of this?



I grabbed a couple of pictures last night.  First is a picture of the boiler and the returns.  I can't figure out what that vertical pipe was for on the far left. An old water feed line? 



The next photos are two more mysteries.  One is a thermostatic valve/radiator trap  which appears to be trapping the drip off of the radiator above it.  Why would they do this?  All I can think of is not enough "A" dimension because they needlessly dropped the return. 



The next one is what is what is basically a short circuit between the main and return.  At this point, there are no radiators beyond it, so it is actually rather necessary.  However, there were radiators after it that have been removed (and the main removed), and I suspect this predates their removal.  Can it be left in place when the downstream radiators are reinstalled and the end of main reconnected to the end of return?



The last one is a spigot at the end of a main.  I'm sure this must have had a purpose at some point.  Anyone seen this before?  Guesses?

ChrisJ

Foam?

Doesn't that foam insulation usually melt on a dry return?

JStar

Steam

The trap looks like a band-aid for keeping steam out of a dry return, instead of dropping into a wet return.



I've seen the "bypass, short circuit" arrangement once before. It had no appreciable effect on the system. Although, when I saw it, there was a cross below every radiator run out.



The spigot is another band-aid. Somebody didn't know how to use a level, and the spigot is their way of removing water from the main.

mcsteamy

Thanks, Joe!

I figured the trap was some sort of band-aid, although I don't at all understand it.  Had they not dropped that a foot after the trap, the dry return would have been at the same level as the other steam-carrying dry returns. 



The spigot still has me stumped, unless it left from the initial install?  The thing is, that main drops to the dry return at exactly the same point as the spigot... Any water is going right down that return, which looks like it has plenty of pitch (although it is somewhat obscured by massive amounts of asbestos cement). 



Thanks for the feedback on the "short circuit crossover".  I'll leave it in place when I repipe the rest of that main, and cross my fingers.  It has about 20 more feet to go to be back to where it used to be to get the room at the back of the house heated.  That will eventually be a 10' cast iron baseboard over a crawlspace, so piping it should be interesting... 



Good news is the trap that I used for a main came early, and works well.  Leaks a waft of steam here and there, but adding an extension pipe to condense any escaped steam should take care of that. 

mcsteamy

Trap

Any suggestions whether I can just remove that trap by pulling out the element?  Turns out if the radiator fills up with steam and a little pressure builds, the radiator it serves (and it seems like, the main) backs up with water--classic "swooshing" sound.  



With the current boiler, there actually seems to be plenty of "A" dimension.  I don't see any reason to attempt to keep steam out of the return--all of the other returns have steam in them. 



I don't think the trap is failed closed--the return still gets hot.  All I can speculate is that whenever it tries to open, steam from the main cuts through and closes the trap again. 

mcsteamy

Update

I forgot to take pictures, but I finally had time to head to the store and pick up a few fittings to get the radiator traps mounted up. Had one done, now have two.  And WOW does that ever work. It's about as much venting as three Gorton #2s.  Orientation of the trap does not seem to matter at all.  a 6" 3/4" pipe threaded into the outlet of the vent and tilted up successfully condenses, catches, and drains back most any escaped steam or condensate.



I might add on a third B&J trap just for good measure if it looks like it would speed it up even more.  As it turns out, even though it appears each dry return has its own  vent, that really isn't true.  I could not figure out why in the world my vents were  closing, yet the dry returns 10 feet farther up the line were not hot yet.  Then I noticed they seemed to be heating up backward.  Turns out the waterline on the "new" 30 year old boiler might be juuuust low enough to expose the "tie together" of the dry returns to air when the  boiler first fires and before pressure is up.  So much for being able to tightly control  the venting.  All I can do (without cutting things up) is vent like a mad man and hope it  works. 

MDNLansing

Thanks

Thanks for posting this update. I was curious about using traps to vent but couldn't find any info about it. Does it give you any back pressure before they close?