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Help Please! Old 2-pipe System

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  • mattmia2
    mattmia2 Member Posts: 9,659
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    Others will have better ideas than I do about testign steam traps. Failed closed is harder to test, you can get some idea about if they are failed open if it is steam hot on both sides of the trap.

    Steam in the returns will cause 2 big problems.
    1. If it reaches the return vent it will close the vent and stop all venting of air from the system.
    2. If it reaches the outlet side of a steam trap through the return before steam reaches the trap through the supply it will close the trap and stop the radiator(or main) from venting air any further.
    3. It can cause water hammer
    Hot_n_Cold
  • Jamie Hall
    Jamie Hall Member Posts: 23,313
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    You can test the traps simply by measuring the temperature drop across them when the radiator is fully hot. The inlet should be at least 5 degrees hotter than the outlet (use an IR thermometer, but be aware that if the finish on the two pipes is different the temperatures may not be accurate. And measure the outlet as far away from the trap as is reasonable...)
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Hot_n_Cold
  • mattmia2
    mattmia2 Member Posts: 9,659
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    If everything is set up right steam should never reach the traps on the radiators.
    Hot_n_Cold
  • Jamie Hall
    Jamie Hall Member Posts: 23,313
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    mattmia2 said:

    If everything is set up right steam should never reach the traps on the radiators.

    True. However, the amount of time and testing -- and precision of control -- required to reach that wonderful state is beyond what most people will be willing to pay for. Ideally, one would have both the precisely adjusted and never to be touched inlet control device and, for the occasion when the pressure gets too high, the trap. Further, there is an assumption made that the system is so well balanced that steam arrives at every radiator at exactly the right time for it to put out exactly the right amount of heat to heat that space that day. Good luck with that one.

    I agree, I'm not a purist. Put the traps on -- they're not that expensive -- and relax. And if you never get the differential pressure too high they'll last pretty well forever. The system Cedric powers has aboout three dozen traps (Hoffmans) which were installed in 1930 -- and haven't been touched since and still work just fine
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Hot_n_ColdPC7060
  • mattmia2
    mattmia2 Member Posts: 9,659
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    there are instructions for the valve about where to set the stop based on the edr it is connected to, right?
    Hot_n_Cold
  • Jamie Hall
    Jamie Hall Member Posts: 23,313
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    mattmia2 said:

    there are instructions for the valve about where to set the stop based on the edr it is connected to, right?

    Yes, there are. They are internal, however, at least on Hoffman valves and a pain. Perhaps more to the point, the markings are correct for one and only one differential pressure (I believe it is 4 ounces per square inch) (the same problem exists for orifices -- they are correct for one, and only one, differential pressure).

    Mind you, I'm not saying that using a steam trap to keep steam out of the return instead of a precisely set valve or orifice is as elegant as the valve or orifice. It isn't, and there's a certain pleasure and pride in getting a regulating valve or orifice system set up properly. But doing that requires that the boiler be precisely matched to the radiation demand (and let's not forget that that varies with room temperature...) (or has a narrow band pressure control) and that the boiler pressure is allowed to reach optimum pressure quickly and then stabilises there, and that someone has been able to take the time and go around to the entire system and set the valves or swap orifices until the whole thing is in balance.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Hot_n_Cold
  • mattmia2
    mattmia2 Member Posts: 9,659
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    If you err on the side of a little less steam in your setting of the valve you will likely still have enough heat and you won't have steam in the returns(if no one has screwed with them they should have been set correctly when it was installed). The homeowner can close rooms that are too hot a little and do the final balancing themselves.
  • Jamie Hall
    Jamie Hall Member Posts: 23,313
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    mattmia2 said:

    there are instructions for the valve about where to set the stop based on the edr it is connected to, right?

    Yes, there are. They are internal, however, at least on Hoffman valves and a pain. Perhaps more to the point, the markings are correct for one and only one differential pressure (I believe it is 4 ounces per square inch) (the same problem exists for orifices -- they are correct for one, and only one, differential pressure).

    Mind you, I'm not saying that using a steam trap to keep steam out of the return instead of a precisely set valve or orifice is as elegant as the valve or orifice. It isn't, and there's a certain pleasure and pride in getting a regulating valve or orifice system set up properly. But doing that requires that the boiler be precisely matched to the radiation demand (and let's not forget that that varies with room temperature...) (or has a narrow band pressure control)and that the boiler pressure is allowed to reach optimum pressure quickly and then stabilises there, and that someone has been able to take the time and go around to the entire system and set the valves or swap orifices until the whole thing is in balance.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Hot_n_Cold
    Hot_n_Cold Member Posts: 60
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    mattmia2 said:
    You might try taking the current vacuum valve out of the air eliminator and leave it open and see what happens, it might be too restrictive for it to vent quickly enough. If everything else is ok there should never be steam in the returns so it should never vent steam, if it does you have other issues you need to find and fix like bad crossover traps, pressure too high, or part of the system that were once below the water line that are no longer below the water line with the newer, smaller boilers. BTW, this is a slog now, but if you keep at it you can be the person that fixes steam problems that others can't. I wouldn't rule out some of it being that the boiler is still throwing water up in to the mains because there is oil on top of the water.
    Yeah, I was thinking of just removing the disc from the check valve thereby preventing vacuum formation. Should work right?
    If it does, then perhaps I could leave it as-is. Or should I go for a Gorton 2? $190
    And not in stock.
    Supply shop said a Gorton 1 could work, but they said I'd need 4 of them to equal 1 of the #2. They didn't specify how to size the main vent. Total EDR/load? Total length of piping?

    And, I do love the challenge. I've been spending countless hours reading, researching, and talking with the helpful & knowledgeable folks such as yourself on here. Super grateful for all this.
    Dan's book is awesome too.
    It's been a time travel through history!

    I added Boiler cleaner after skimming the first time. Hasn't been running since though. Just sitting in there.
    I'll try skimming again.

    Thank you!
  • mattmia2
    mattmia2 Member Posts: 9,659
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    You should put a vent in there, but you can test without anything in the tapping. The one that @Steamhead recommended probably vents a lot faster than the original which was probably mostly intended for coal and a very massive boiler which would heat slowly and not start producing steam as fast as a modern relatively low mass boiler. Your problem with the water leaving the boiler isn't the vacuum vent, or at least the vacuum part.

    Too much detergent in the boiler will cause it to prime(foam) and throw water in to the mains that way.
    Hot_n_Cold
  • Hot_n_Cold
    Hot_n_Cold Member Posts: 60
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    So I putmattmia2 said:
    You should put a vent in there, but you can test without anything in the tapping. The one that @Steamhead recommended probably vents a lot faster than the original which was probably mostly intended for coal and a very massive boiler which would heat slowly and not start producing steam as fast as a modern relatively low mass boiler. Your problem with the water leaving the boiler isn't the vacuum vent, or at least the vacuum part. Too much detergent in the boiler will cause it to prime(foam) and throw water in to the mains that way.
     The vapor stat & low pressure gauge on. Boiler fires up, air eliminator whistles, pressure rises to my set point of half psi fast. Burner kicks off, water level drops to like half sightglass, bounces. Air eliminator still whistles. Pressure gauge drops to zero, burner doesn't come back on.
    It'll short cycle once every few mins. Radiators not getting hot.
    So I removed the little disc in the check valve to see what happens. Next step is putting that main vent on.
    Here's a pic.
    Half psi main, 4 oz diff

    Another update : gonna try removing air eliminator all together and just putting a main vent on top of end return main.
    I only have a Gorton 1 with me today.
    Gonna try that to get by and then maybe return with a #2
  • mattmia2
    mattmia2 Member Posts: 9,659
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    What if you take the whole vent out? It looks like that is pretty restrictive especially if there is a thermostatic element in that little housing too.

    If it is shutting down on pressure before the radiators get hot there isn't enough venting.

    I'm not convinced it isn't also surging or priming.

    Hot_n_Cold
  • Hot_n_Cold
    Hot_n_Cold Member Posts: 60
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    mattmia2 said:
    What if you take the whole vent out? It looks like that is pretty restrictive especially if there is a thermostatic element in that little housing too. If it is shutting down on pressure before the radiators get hot there isn't enough venting. I'm not convinced it isn't also surging or priming.
    I removed the entire Air Elim assembly. Running main cutoff at 1.25 psi.
    8 oz diff.
    Not short cycling as badly.
    All radiators warming up.
    Balanced them using the adjustable inlet valves.
    Now I'm noticing bubbles in sightglass. Still surging and bouncing.
    Might skim again and check pH.
    However, I did just add boiler treatment. Does that cause foaming?
    It's definitely working better than it did with air eliminator & check valve.
    Probably gonna get the Gorton #2, skim again, and adjust pH.
    Here's some pics for your viewing pleasure.
  • mattmia2
    mattmia2 Member Posts: 9,659
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    That foaming means you have too much "treatment" in it, that is called priming, the foam will carry water out of the boiler. Drain some or all of it and add more water.
    Hot_n_Cold
  • mattmia2
    mattmia2 Member Posts: 9,659
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    You could also drain water out of the skim port first to see if you bring more oil out. It could both still have oil in it and also have too much detergent in it.
    Hot_n_Cold
  • Hot_n_Cold
    Hot_n_Cold Member Posts: 60
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    mattmia2 said:
    You could also drain water out of the skim port first to see if you bring more oil out. It could both still have oil in it and also have too much detergent in it.
    Will do asap. Can't get back to it til early next week. Should be safe to run over the weekend right?
    If not, I'll try to get back tonight.

  • mattmia2
    mattmia2 Member Posts: 9,659
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    Are the returns cool or at least not steam hot? if you're getting steam in the returns you need to figure that out.

    I don't know about the priming. I'll defer to others.
  • Hot_n_Cold
    Hot_n_Cold Member Posts: 60
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    mattmia2 said:
    Are the returns cool or at least not steam hot? if you're getting steam in the returns you need to figure that out. I don't know about the priming. I'll defer to others.
    Yes the returns are cool.
    Also, that crossover from end of steam main to end of return main with the trap is cool. As it should be, from what I understand.
    Only 1 radiator isn't getting warm. It's the one furthest from boiler.
    Also, it'll run okay for hours but I guess it starts hammering during night time and then that last radiator gets cold.
    Returning to add more venting & do some purging & skimming . Will report back asap.
  • mattmia2
    mattmia2 Member Posts: 9,659
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    The ends of the mains drop down in to the wet returns and the wet return forms a water seal that keeps the steam out of the returns. If that isn't low enough below the water line the pressure of the steam can push the water out and steam in to the returns.

    If the water line in the boiler is falling that could turn those water seals from low enough to not low enough. It is normal for the water line to fall some later in the cycle as steam and condensate are out in the system.

    Maybe the steam trap in that radiator that won't heat after a while is clogged up so that condensate can't drain out relatively quickly and that radiator slowly fills with water.

    There are other possibilities here for both.

    I'm not quite sure what the "air eliminator" does besides act as a vent and to close off the vent to equalize the pressure with the return if the pressure in the main gets too high (and i'm not sure it does that when it isn't combined with the return trap). It is possible is serves some function of allowing water to move from one part of the system to another than you have eliminated by removing it which also could be the cause of your water hammer after a period of time.
  • Steamhead
    Steamhead Member Posts: 16,842
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    .......Also, that crossover from end of steam main to end of return main with the trap is cool. As it should be, from what I understand.....

    Nope. That should be hot up to the trap and warm underneath. This is the "main vent" for the steam main- only difference is it discharges into the dry return rather than the air in the boiler room. Obviously it's not working.

    Replace that with a 1/2" Barnes & Jones Big Mouth Crossover Trap and I bet you see a huge difference.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    mattmia2