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Leaking vent on return?!

Dsisson
Dsisson Member Posts: 92
I just purchased a new home. I’m familiar with steam, but this system is much larger than what I’m used to. On day 1, I noticed that this vent is leaking liquid water. It’s on a return, right after a steam trap. The prior owner had told me that he thought this vent was undersized, and I did note that eventually it started sucking a lot of air. What the heck is happening here? I don’t understand why it’s leaking?!  


Comments

  • BobC
    BobC Member Posts: 5,477
    That's a Gorton #1 air vent, is it leaking from the thread or from the air hole at the top?

    If it's leaking at the thread unscrew it and clean the theads and then apply pipe dome and teflon tape and install that back where it came from. If the leak is coming from the top that vent has probably failed, before replacing the vent make sure ir's big enough for the piping - you may need a higher capacity vent.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    It's probably there in the first place to relieve pressure on outflow line from that trap. Which makes me wonder... why is that trap there at all, and what could be building pressure downstream of it?
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JUGHNE
    JUGHNE Member Posts: 11,060
    edited April 2022
    That F&T trap date code indicates it was built in Feb 1997. Does it look like it has ever been opened?

    Note:.....Also it could be 1979.....book isn't clear....have to go by the looks/condition for which choice.

    If it is working, stopping steam and then passing condensate water, that could be an open pipe vent....in theory.

    Where does that trap drain to?
    Pump or gravity return?

    Pictures of the end of the drain line please.
  • Dsisson
    Dsisson Member Posts: 92
    edited April 2022
    OK, I'm new to the concept of steam traps, and I don't completely understand what they are for. The condensate comes down multiple returns, each with a steam trap, and they all collect into pipes below the slab, and come back to the boiler via gravity. I don't think there's a pump. I do not know if the steam trap has been opened, but previous owner has replaced some. If I need to do maintenance to the trap, please direct me to what I need to do. I'm very hands on.

    The vent seemed to be leaking from the base - NOT at the threads but above them.

    Can I assume this means that the condensate is backing up too far? How can that even happen?

    PS: can someone give me the "for dummies" reason that you use steam traps? I don't see why the condensate doesn't just drain down, why does it need to stop?

    A bit more background - this is a very large historic house. It is all steam, but somewhat unique that the first floor is heated with a "forced air" system, which is a radiator that the condensate/return water goes through. Air blows over this radiator (radiator in a metal box) that then goes up through the floor - there are 4 or 5 of these. All the returns go through these, and then have a steam trap on the outlet side. The balance of the house has typical 1 pipe system with radiators. Now that I think about it, this does not make much sense, because if it's a 1 pipe system, wouldn't the steam also go through these 1st floor "forced air" radiators? Maybe it does. I've only owned the house for 2 days, so still wrapping my head around how it works. On the plus side, everything is working great, minus the leaking vent.
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    OK. Now we're making a bit more sense. Steam traps are needed so that steam does not get into the condensate returns and pressurize them. Only water or air is supposed to get past them.

    Your big underfloor radiators were common enough in some fancier houses. But they are steam -- no condensate, although depending on how the steam mains are pitched they may also handle some condensate. This means, though, that they have to be above the water line in the boiler -- in fact, at least 28 inches above the water line for every pound of pressure the boiler creates -- unless there is a condensate receiver and boiler feed pump, which you don't have.

    Which brings up a dismayingly common problem: running the system at too high a pressure. Without knowing how the rest of the system is piped -- nor how high those basement radiators are above the boiler -- I can't really be sure what your boiler cutout pressure should be, but certainly not more than 1.5 psi and, quite likely, less. Otherwise condensate will back up to those traps and vents, which you do not want.

    A slightly related problem is that it isn't uncommon -- unfortunately -- for a replacement boiler to have been installed at some point, and the installers paid no attention to the required water level. More often this results in the water line being too low -- but it's not unheard of for it to wind up too high.

    Some exploring in the basement is in order here!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JUGHNE
    JUGHNE Member Posts: 11,060
    Pictures of the boiler, floor to ceiling, showing piping from several angles would help out a lot.

    And can you trace where the pipe with the air vent ends up at the boiler?
  • neilc
    neilc Member Posts: 2,702
    when can I say pigtail ?
    known to beat dead horses
  • Dsisson
    Dsisson Member Posts: 92
    edited April 2022
    I'll take a bunch more pictures this evening and post them. If nothing else, I'll learn more about the system from all of your wisdom, and you'll get some views of an interesting system. I'll have this thing whipped into shape in no time with your help. I think the pressures are decent, but I am aware of what pressures it should be at, so I'll post some questions about adjustments too. It seems to have 2 presuretrols (can't remember the brand right now), so maybe one is a cut in and one is a cut out?

    The pipe with the air vent (the leaking offending one) goes into the basement floor, and pipes back to underneath the boiler. It's a return.

    PS: the basement ceiling is approximately 9 or 10 feet. The underfloor radiators are probably 2 feet below that, I'd guess 5-6 feet from the water line to those radiators. I can measure that later on.
  • neilc
    neilc Member Posts: 2,702
    old returns, under slabs, are susceptible to leaking, and or clogging,
    clogging could be another reason(pressure) water is up at that vent,

    do you have any idea, or a feed meter, to know how much water is added to the boiler daily, weekly, monthly ?
    how would repiping above the slab work for you in that basement?
    known to beat dead horses
  • Dsisson
    Dsisson Member Posts: 92
    neilc, The prior owner explained that the system USED to collect the condensate to a tank, then push it to the boiler, but that system was a retrofit and wasn't working properly. He cut the slab and repaired the original under slab returns to get it working "correctly" in his opinion. So, I'd assume the underslab returns could be clogged. I did discover (this morning) a capped valve at the underslab system, I'd guess that the valve has failed and they capped it...but the whole point of it was to clear crud out of the return system. I'll uncap it soon and see what junk comes out, maybe add on an extension and another new valve. It's kinda exciting to learn about a new, larger system. I'm just a homeowner, but I find steam fascinating, and absolutely love living in homes with steam systems. So much more character and better heat IMHO than anything else. This system is enormous, I counted 10+ radiators (last night) that had minor leaks from the shut off valves (yeah, I can't wait to solve those problems) so I'm thinking there are 20+ radiators on the system. This is a "museum house" ... prior owners did a great job preserving it, but prioritized preservation over (function I guess?)... lack of leaks? My wife is an architectural historian, I'm an architect...we both want to preserve it but live in it too. I'll post a bunch of photos later. To answer your question, I don't know how much feed water is coming it. I'm honestly confused HOW feed water gets into the boiler. Prior owner said there's an autofeed, but I don't see it. I'll post some pics - that's a whole 'nother question that I have (how TF does this thing water feed???).
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    I've sent you a PM
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • pedmec
    pedmec Member Posts: 968
    the reason why its sucking air is because you have trapped steam between the f&t trap and the underground piping. when the steam condenses it starts forming a vacuum which will open the air vent and start sucking air into system. the f&t traps should not be on your system if you have a gravity return. your not clogged. your condensate is backing up into the return to try and overcome the steam pressure in the boiler. if you remove the f&t you will have left over steam pressure in the return to help overcome the pressure in the boiler. that's why you have condensate pumps. the pumps will push the condensate back into the boiler.
  • Dsisson
    Dsisson Member Posts: 92
    I was busy the last two days. Update-

    first, I replaced the offending gorton #1 with a ventrite #35 (too small but it’s what I had, gorton #2 on order). The leak stopped. 

    But I discovered rusted 2” main. 3 rust spots. I replaced it, total of about 15’ of main. 

    Also drained from the return system, lots of muddy water came out but no chunks. Drained the boiler itself too, and topped up with fresh water. Ran the boiler up to temp for several hours, and everything seems to be working properly. 

    Now I’m mostly concerned about the rusty pipes. At my other place, the mains are clean and dry inside, but obviously this one isn’t. I expect I’ll be replacing more rusted steam line in the future, so I’m going to look for a pipe threading machine, gonna need it. 

    Posting a bunch of pictures for your edification. 

    Reading the steam traps, I expect they are needed. They exist at every under floor radiator, and at the ends of the mains. Each one has an air valve after the steam trap-the air valves are a mix of gorton #1 and ventrite #35


  • neilc
    neilc Member Posts: 2,702
    edited April 2022
    if you haven't, it may be worth your time to check and clean the trap and piping to the Ptrols and gage,

    as a quick check, remove the gage, and see that you can blow thru the pipe back to the boiler,
    there would be some resistance as you clear water in the trap, but then it should freely breath,
    add water back to the trap as you reassemble,

    if there is resistance that does not clear,
    you're set up well with plugs on tees and crosses to open up and do a more thourough cleaning,
    again, prime that trap going back together,

    do you see pressure build on that gage?

    hashtagging pigtail
    known to beat dead horses
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    Did you get the PM I sent you?

    On the strictly heating end of things. Yes, you do need traps on those under floor radiators. The vents on the outlet side will do no harm, but...

    There must also be venting on the INLET side. This may be built into the traps. It the radiators are heating properly, then those built in vents are working, and they are probably adequate. Just barely...

    On the rust in the steam mains. This tells you that for many years water has been backing up into them. Pressure is absolutely critical on this system. The clear faced pressuretrol is the safety backup in case the regular one fails for some reason. The one with the single scale is the control pressuretrol. If you can swing the cost, a 0 to 4 psi vapourstat would serve you much better, however. If you can, substitute that for the single scale (404 type) pressuretrol, and try it at 1 psi cutout and 0.5 psi cutin.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Dsisson
    Dsisson Member Posts: 92
    The gauge does not build pressure. I assume that it's no good because it doesn't have a pigtail, right? In fact, there's no pigtail on the pressuretrol either, so I assume I should put one, right? Actually, put 3, because there's 2 pressuretrols plus the gauge? I do intend to dial it in, and I do have a 3 psi gauge, so I can do that even if the 30 pound gauge isn't working.
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    There are two reasons the gauge may not build pressure -- or at least seem not to. Well, actually three. If the gauge is the standard - to 30 psi gauge, it won't register the low pressure the steam system should run at anyway. Second, it's possible that the gauge may be busted. If it is, don't worry about it.

    The third and happiest is that the system may be working just as it should! Steam heating systems aren't intended to build much pressure -- many, and I suspect yours from what I've heard of it so far -- are perfectly happy running on less than half a pound of pressure, and if yours can consistently do that and heat the house, it just means that the boiler and burner is well matched to the radiation in the house.

    Pigtails are never a bad idea, but whether they are actually needed or not depends on the way the piping is arranged. The idea is to keep steam from reaching the gauge or pressuretrol by providing a water seal in between the steam and the device. Pigtails are the simplest way to do that, but there are other approaches as well.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JUGHNE
    JUGHNE Member Posts: 11,060
    You have a water trap control "tree".

    The very top small pipe coming off the top left of your boiler has a built in trap.
    It drops down, over and back up....that is full of water.

    There is about a 6" water seal before your controls.

    All those plugs and caps are installed so you can open and inspect/brush out that 1/2" piping/fittings. When done then add water again.

    You can add another gauge by extending the 1/2" manifold, adding another 1/2 X 1/4" tee to match what is there now.

    I have built that setup several times. But use 1/4" x 4" brass or SS nipples for the riser to the component.
    If the 1/2" piping/fittings are clear upon inspection then the 1/4 brass/SS risers would be clear also. The black pipe collects sludge quicker than the 1/4" risers.
  • JUGHNE
    JUGHNE Member Posts: 11,060
    Could you show us what is in the pit behind the boiler, I assume your pump, but would like to see the piping connections down there.

    Also there is a condensing unit on the floor near the bottom of the steps.
    You must have a walk in cooler or large fridge/freezer above?
    What is really unique is the (what appears to be) lead piping for the drain down to the funnel.
    Then a drum trap on a shelf with the same material piping in and out of it.
    That dates back a few years. (R-12 switched to R-409A)
  • Dsisson
    Dsisson Member Posts: 92
    Yes, the old condensing unit on the floor feeds a big fridge in the 1st-floor kitchen. It's a former icebox, converted to a fridge. It does work. The drain down is for the ice - with the funnel to prevent bacteria from going back up into the fridge. It's not used anymore. Lots of drum traps in this house.

    Behind the boiler is the pit. There's no condensate pump, everything collects in the pit and pipes to the boiler. If you look in the photo of the front of the boiler, there's a tank to the right side. The former owner explained that it was a tank to collect the condensate, and it does have a pump back to the boiler. Now it's disconnected but still acts as an auto water feed for the boiler. I admit I don't understand this yet.