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main vent

with the help of the forum, I've been fine-tuning my 2 pipe system. It has been suggested that i replace the main vent (Dole#5) with a Gorton #2. The Dole has been in place more than 30 yrs, so this seemed like a good idea. Today I replaced the Dole with the Gorton #2. Since overhead space is limited, I added an 18" antler and installed the Gorton .

Fired up the boiler, and shortly thereafter, the Gorton started gurgling and spitting water. The gurgling has stopped, but it's still spitting water.



Pressuretrol is set at .5 with a +1 differential. According to the gauge (which is probably 15 yrs old) boiler is starting up at 0 pressure and shutting down at 4-5 lbs.



Is it possible that the system is full of air--since the Dole was there forever ? And it occassionally spit water also.



System has a differential loop. Do or should these be drained and cleaned periodically, and would a plugged loop be causing the water spurts from the main ?/

Comments

  • RDSTEAM
    RDSTEAM Member Posts: 134
    some ideas

    make sure the vent is atleast 15" from the end of the main.  replace the gauge and make sure that your pressuretrol is working. no reason for it to be up around 5 psi. im not following with the differential loop. what are you reffering to? 18" is more than enough, you only really need 10". system cant be full of air unless no venting was being done (this would have definately been noticed because you would have no heat anywhere) and as soon as you took the old vent off you would have removed this air.
  • turbobike
    turbobike Posts: 28
    main venting

    differential loop is a Hoffman Differential loop which ties main steam pipe w/return line.

    Old main vent (the Dole) was on top of the Hoffman loop. Because of vent size and space limitations, I antlered the Gorton 18'' from the previous mounting spot.
  • Jamie Hall
    Jamie Hall Member Posts: 17,183
    Two things...

    That vent shouldn't be spitting.  Make sure that any horizontal pipes in your setup have a good positive pitch back to the main, so that condensation in there can drain back to the main and not collect in the antler.



    Differential loops need no service at all -- in fact, I would suggest that you don't even try to take anything apart there.  They were factory assembled.  However...



    HOWEVER!



    A system with a differential loop on it must never have the pressure go over 6 to 7 ounces.  Period.  At that pressure, the loop is designed to function, and will function, and what it will do is let steam, at boiler pressure, into the dry return.  It's supposed to do that.  This will close the vent (assuming that the vent is right near it, where it is supposed to be) and allow condensate to return to the boiler.  Which it is also supposed to do.  However, this will also stop steam from moving in the system.



    So.  Bottom line.  Scrap that pressuretrol and get a 0 to 16 ounce vapourstat and a snubber (you need that, to dampen small pressure variations which will cause false trips).  I would start by setting the vapourstat at 6 ounces, with a 5 ounce differential (the differential on a vapourstat is subtractive).  Should help a lot.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • RDSTEAM
    RDSTEAM Member Posts: 134
    Gotcha

    Im hearing you now. jamie beat me to it. crap!! pressure too high. fix it and you will be golden.
  • Jamie Hall
    Jamie Hall Member Posts: 17,183
    I should add

    that assuming that the new Gorton is on the dry return, near the differential loop where it belongs, fixing your pressure problem will fix your spitting problem.  But get that pressure problem fixed pronto -- not only is it probably the direct cause of the spitting, but it's costing you a bundle, and it is almost certainly damaging (if it hasn't already destroyed) all your traps.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • turbobike
    turbobike Posts: 28
    main vent

    what you are saying about the pressure makes sense. I'll replace the pressuretrol.

    Regarding the Hoffman loop---it has a drain plug at the bottom of each leg. I pulled one off many yrs ago, and mucho crap drained out. If both legs are crapped up, would this prevent the loop from functioning properly ?
  • RDSTEAM
    RDSTEAM Member Posts: 134
    edited March 2011
    it sure would

    if any one of us were all crapped up, we wouldnt work properly either.



    give DH method of cleaning a steam system a shot. should definately get things running smooth.
  • Jamie Hall
    Jamie Hall Member Posts: 17,183
    There were two

    flavours of differential loop -- one with two pipes, and one with one large pipe (there is actually a smaller pipe inside).  If you can get the drain plugs out of either one without cracking anything, that will help -- certainly no harm.  However, when they trip they tend to purge themselves (up to a point) so it is less of a problem than one might suppose.  Also, they take a few cycles after the plug has been opened to drain them for them to begin to function properly again (paradoxically, the better your near boiler piping, the longer it takes for them to recover!).  There is a priming plug on the top which can be used to put water back into them to eliminate that lag -- but that plug can be a bear to get off without cracking.  Which you really don't want to do...



    I suppose that if one were really plugged it wouldn't operate at all... but it would have to be really badly plugged.



    You can sometimes tell if it has tripped: the dry return just above it will be warm or steam hot, and get cooler as you go farther away (if the dry return is hot all along, or gets hotter as you go away from the differential loop, you've got a leaking trap somewhere).
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • turbobike
    turbobike Posts: 28
    main vent related

    Any specific recommendation on which Vaporstat to choose ? I see a couple of Honeywells in the 0-16 oz range.
  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,552
    .

    It's the L408J1009
  • crash2009
    crash2009 Member Posts: 1,484
    L408J-1099

    L408J-1099
  • Paul Fredricks_3
    Paul Fredricks_3 Member Posts: 1,552
    .

    Honeywell doesn't list a 1099 on their website. I think it's the 1009.
  • crash2009
    crash2009 Member Posts: 1,484
    oops!

    tax-time typo.

    L408J-1009  I got a pretty good price here.

    http://www.energyequipment.com/searchdbs.aspx
  • turbobike
    turbobike Posts: 28
    main vent-update & more questions

    So.....antler w/Gorton still filling with water. Antler not quite level, so I removed the antler and (due to space restrictions ) I installed Hoffman #75. (Same physical size as the Dole it replaced) Today I installed a vaporstat (with snubber). Set it at 6oz w/4 subtractive differential. Boiler runs about 1 minute & shuts off on pressure. Pulled the Hoffman & it's full of water. Took the plunge and pulled the drain plugs on the Hoffman Differential loop.

    Right side was full of very black water (like used diesel oil) . Left side was also very black water--THEN clumps of "mud" began draining ! Probably got about 4 oz of goop from there. Snaked as best I could w/a piece of wire. Reinstalled plugs and reinstalled Hoffman vent. Fired up boiler---and, for once, I could hear AIR leaving the vent ! Boiler is still running for about a minute, then shutting down on pressure. Back on in about 4-5 minutes. At this low pressure, is this considered short-cycling or normal?

    I'm making progress, but system isn't right... yet.

    Now my questions--

    1. -Hoffman Differential loop---1 side is hot-other side is 1/2 cold & 1/2 warm. Normal ?

    2. Hoffman #75 vent.....will it be/is it ..OK after being filled with water ?
  • Jamie Hall
    Jamie Hall Member Posts: 17,183
    I'm beginng to wonder...

    if there isn't some other kind of problem here.  Like a piping problem.  Reading your post, it sounds to me as though you have the smaller two pipe version of the differential loop.  If that is the case, you should have a connection from the steam main or header to the larger of the two top openings.  The vent, or vent antler, goes on the other top opening.  The side opening is connected to the dry return.



    The larger, single pipe version is piped a little differently...  Look at Lost Art, page234.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • turbobike
    turbobike Posts: 28
    diff loop

    Yes, I have the 2 pipe version ( a #1 loop) , piped as you describe
This discussion has been closed.