Help with 30's era (?) 1 pipe steam/ premature air vent fail

xmorganx

@Steamhead , @BobRohr , and anyone else. I would really appreciate a helping hand.

A forward, if you will.
I do a lot of (Read: deal with a lot of different types of existing) hot water systems.

I do not do steam. There is very little in my market (non-existent on light residential, extremely rare on heavy residential (appt towers), every so often on commercial. Used in heavy industrial and our little section of district heating, but definitely a specialty. Not my specialty). I have almost no experience with it. What little base knowledge I have is both dated and vague.

ETK ("en tout cas", means "anyways"):
I recently inherited a building with steam to my client list. There has been very little maintenance for the past 15 yrs or so. The new concierge has decided to take charge and deal with all (or at least the most urgent) of the problems. This all started because there was a main vent in the "entretoit" (that space between the ceiling of the top floor and the roof decking, "attic" maybe? In this case a more or less 3 foot crawl space with surprisingly good lighting, a lot of asbestos and a whole bunch of pipes) that was leaking onto the ceiling of the appt below. He called me to come replace the leaking vent (Hoffman # 75). Which I did. Then he asked if I had a bit more time to help him out. So we went exploring.
The building is 30's, maybe 20's. 7 floors, 30 or so appts.
As far as I can tell, it is 1-pipe steam with a giant (at least 4, maybe more) steam main running around the basement, with numerous 2 in risers along the perimeter, each serving 2 rads per floor. In the entretoit, all these risers connect to what I assume is a condensate collector (hard to tell because it is insulated, at least 2, possibly the dreaded 2 1/2 or more) which also runs the perimeter. (It is possible that I have understood the flow backwards, as I said, I do hot water, not steam)
Not all the risers have main vents
Certain appts (all seemingly on the same two risers) are complaining of "noise". When I was there I could hear gurgling, but some of the descriptions sound more like water hammer. There are a few rads that have an obvious counterslope, so that needs to be dealt with. I hadn't thought of the disk issue @Steamhead mentioned, so will check that next time I'm there. The questions (you may all laugh at me):
1- How does one "dry" one's steam? Because their steam seems rather "wet".
2- Shouldn't all the risers have main vents? I want to propose adding them to the client because it makes sense in my hydronic head, but please let me know if I am wrong.
3- The most important one. Another part of my initial call was to deliver a whole bunch of new air vents the client had ordered as spares. On my exploration tour, I discovered that most of the existing vents are relatively new, but have failed. What should I be looking for to help me solve the mystery and stop wasting vents?

I appreciate your help.
Thank you

clammy

You should check the operating pressure the boiler is set for and be sure it not set above 2 psi . Being no one has done any service possibly it would be time to start.
Flush the boiler of build up of mud and debrie greatly effects dry steam production and boiler eff . Flush out wet returns also ,the sight glass assembly should be removed and cleaned and same goes for any float type low water cut off . Some times when a boiler is slightly over filled and operating it will produce more carry over because of the higher water line ,so check that also . If it’s a one pipe system there should be main vents at the end of the steam mains . In some cases older building which had been coal fired lack any main venting due to the fact there was really no controls so once it was banked and firing you had heat for hours till it was exhausted hence the reason main vents where not to common ,2 pipe a different story .
Are your steam mains insulated if not then except gurgling and spitting vents ,steam pipe should and need to be insulated . Unless you like leaks and repair bills ? Insulate .if most if not all is out of your skill set then you should find some familiar w steam and who is willing to do the maintance instead of replacing . I can only wish you luck and if your not going to do it yourself then good luck and if you find some one willing to do the maintanance correctly be sure to just pay the piper . Steam system usually operate just fine but if no one does annul maintance then it turn to crap extactly where your at
Peace and good luck clammy

Waher

I think this may be a Mills top feeding steam system and the large pipes in the basement are the returns. With that attic space being the distribution mains feeding downward. That single Hoffman 75 probably originally was some football sized vent that should be replicated with a vent antler (manifold) of multiple Hoffman 75s or Gorton No2s.

Turn the pressure down to 2 psi, preferably 1.5 psi. Clean the pressuretrol pigtail and post pictures of the near boiler piping.

https://www.heatinghelp.com/news-and-media/dead-men-tales/the-mills-system-surprise/

dabrakeman

Pictures help.

xmorganx

So someone who is not me did do the boiler maintenance this year. I'm going back tomorrow, so I'll check it out, but the sight glass etc seemed OK. I'm intrigued about this Mills system business- I will investigate further tomorrow. As for the Hoffman 75: That's the weirdest part (to my hydronic brain, anyways). It's not even on the main. It's on this one random riser and was clearly added after. There's a 1/4 in (maybe 1/8 even) tap added into the pipe and a reducing coupling to bring it up to 1/2 in. Not saying it was done yesterday, but I can still see the stains from the plumber who didn't bother to put down cardboard underneath when they did the tap. The 5 or so visible risers on either side have nothing. I will explore further on a quest for a football sized vent.

Steamhead

I think @Waher is right- this sounds like an overhead-distribution or "Mills" system. You probably have a large steam pipe coming up to the attic from the boiler, and the main with the vent on it feeds steam to the "drop risers" in which the steam flows down to the basement.

In this type of system, it is essential to vent the bottoms of the risers so the steam will flow down quickly. The vent in the attic would then be responsible for the main riser and the attic piping. Big vents are essential for quick steam distribution. I like the Gorton #2.

If there is a condensate receiver such as a boiler-feed pump in the basement, you will need to add traps to the bottoms of the drop risers to keep steam out of the tank. One trap at the tank won't work.

Post some pics and let's have a look. Where is this job located?

EBEBRATT-Ed

Your sure it is not a gravity hot water with an attic expansion tank?