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Cold room and main venting

Hi all – looking to help a friend out with what I hoped would be an easy project but you know how that goes.

Background: 2 story house with one pipe steam. No main vents. Purchased 7 years ago with no boiler maintenance done in at least that long. The second floor has a room, lets call it the study, that has never had “working” heat which we’re looking to fix. The study is the last radiator on the end of a 45' run in the basement with a riser to the second floor.

So Far:
  1. The first floor had Hoffman 1A vents all set to fast. Some were broken and releasing steam. I replaced all of the first floor with Gorton #4. On the second floor I put a #6 in the warmest room, a #C in the second coldest, and a #D in the study. During normal operation the study never even gets warm but the other rooms seem to be balanced relatively well.
  2. After a very deep setback the study radiator will get warm after 1.5 hours but spews water and the thermostat will hit temp before any significant heating occurs.
  3. After a very deep setback the boiler was flooding. The sight glass would empty, the LWCO would trigger (correctly), the auto-feeder would kick in, and then after the condensate returned it would flood. I disabled the auto-feeder and the condensate returns in roughly 4 minutes. Everything works fine with it disabled but I assume I need a feeder with a longer dwell.
  4. The water was dark brown so I drained the system several times. I removed blockages in the sight glass valves and cleaned the pigtail. The system has not been skimmed – hoping to find a professional to do it along with any other work I cannot handle.
  5. I installed a low-pressure gauge off the same pigtail as the pressuretrol. The system takes 90 minutes to pressurize at which point water, not steam, spews in the study. The pressuretrol was set to .5psi cut-in and 1psi differential but during observation cut off at .5psi and never cut-in until I tapped the lever even though the low-pressure gauge was at 0. I adjusted to ~1.5 cut-in and 2 differential. The pressure never built higher than 1psi so I couldn’t check cut-in after adjusting. I assume this needs to be re-calibrated or replaced, preferably with a vaporstat.
  6. The loop in the basement takes ~70 minutes to heat up at the riser to the study.
  7. Thermostat was not set for a steam system. This has been corrected and set to 2 cycles per hour.
I’m attaching pictures of the system which hopefully show enough! I know I need main vents but I’m not sure where and if that would solve the issue or if there is additional work needed. Any advice appreciated. Also looking for a contractor recommendation in Buffalo NY – Did not find one on the search.



  • Steamhead
    Steamhead Member Posts: 16,832
    Those capped/plugged tees can be used for vents. The location isn't quite optimal, but as long as the pressure is kept properly low and the system doesn't flood, you should be OK.

    How long are your steam mains, and what pipe size?

    Also- that's a Dunkirk boiler, though it might have another brand name on it. Whoever installed it completely disregarded the installation instructions. Not only is there no proper header, but they reduced the size of the steam outlet from 2-1/2" to 2". This is likely causing water to be drawn up from the boiler with the steam.

    Any steam guys in the Buffalo area?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • KC_Jones
    KC_Jones Member Posts: 5,737
    Boiler is piped wrong, the way it is could be a big part of the water issues.  You shouldn’t get water if any quantity out of a vent, if you do there is a problem with pitch, sags, or poor piping.  Could be all of those.

    Check the overall pitch, the highest part of the entire main should be at the boiler with continuous slope down until it gets to the end and turns down for the return.  Then the return should have continuous slope down until it gets back to the boiler or drops to the wet return.

    Definitely need main venting.  The entire main should be hot in 5 minutes or less.  This is probably the main reason the study gets no heat.

    The vents on second floor are probably all too big, the partial balance you are seeing is luck, you can’t get it fully balanced due to the lack of main venting.  No radiator in the entire house should start heating until the entire main(s) is hot.  The pictures you marked cap/plug are were you can add main venting and probably where it once was, why people remove and cap them is beyond me.

    We’ve seen people asking about Buffalo before and I don’t recall anyone in that area, perhaps someone else knows.

    We can work you through some of these items, the boiler piping is a tough one.  If they want to re pipe it, or replace it.  They would either need to find a contractor that knows, or one that can turn pipes and is willing to listen. The details matter on steam.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    Back to that study radiator. Somewhere in the piping to it there is a length which is pitched wrong and is holding water. May be an interesting bit of detective work to find it...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • matrixfan
    matrixfan Member Posts: 4
    The study radiator does have a horizontal run under the floor about 6". I raised the entire thing 1/2" +pitch which stopped water hammer in the wall after a long fire time. There are dirty water stains around the valve so I will repack it as well.

    I didn't measure the piping and it may be a few days before I can get back to do that and check pitch on the mains and returns.

    The long run to the back of the house (with study off riser at end) is 45' and the front run is 25'. Plus the matching dry return if that is counted. Would I be able to vent off the existing tees at the end of the dry returns? I'd much rather deal with the copper than try to break open the plugs on the mains. Attached is a diagram with what I had in mind.

    Everyone on this forum is incredible. Happy Thanksgiving!
  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    If that "dry return" is an extension of the steam main -- no traps or water seals or what have you isolating it -- it's quite acceptable to place a main vent anywhere along it.

    And now I wonder about the pitch of that steam main and that "dry return". The study riser -- our problem child -- comes off of that? Is there any drip to a wet return somewhere at that distant end?

    Because if not, that may be part of the problem. That piping arrangement -- steam main and steam main extension or "dry return", must all slope down to a drip somewhere, perhaps at the boiler (the ones in your picture).
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 15,517
    If you put the vents on those tees raise then up to the subfloor as high as possible to help keep the water out
  • matrixfan
    matrixfan Member Posts: 4
    Here's an ugly panorama I put together.

    The study riser does not have a wet return and is about 25' from the next riser by the washing machine.
  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    The sight glass would empty, the LWCO would trigger (correctly), the auto-feeder would kick in, and then after the condensate returned it would flood.

    There are no doubt a variety a issues but to me, none of them should be even considered until after this one is fixed. Steamhead mentioned it but I will say it stronger:

    your boiler is piped wrong and boiler water is unfortunately being carried into your system. This will wreak havoc with your vents, can result in water hammer and even radiators shooting water into your rooms.

    trying to fix or adjust venting is pointless while this is happening for several reasons.

    ps: it’s not the condensate that’s making it flood, it’s gallons of boiler water returning. A subtle but important distinction 
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • The main vents will eventually be needed, so no harm in addressing that now-just don’t expect a quick fix for the water carryover/vacuum.
    For that, skimming is also needed, as the oil never disappears, without that important step.
    Keeping the pressure down is worth doing as well.—NBC 
  • ethicalpaul
    ethicalpaul Member Posts: 5,701
    The dirty water getting pushed into the main can foul main vents
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • motoguy128
    motoguy128 Member Posts: 393
    edited November 2021
    Upstairs I would use all Gorton 5’s or 4’s up there after you speed up the main venting. Could save some money and just use Maid o Mist. Same vent rate, cheaper and orifices are interchangeable. Or use Emerson Ventrites that are adjustable between about a Gorton 4-6 range.

    You normally want the upstairs to take just a tad longer to heat up since it tends to overheat anyway unless it’s a very high mass brick house. I have TRV’s on most of my upstairs, but you need a conventionally undersized boiler for that to work.

    Also, ideally, the dead men installed your main so that it starts in the North corner of the house and ends in the West. So the radiators on the mostly shaded side of the house heat up slightly sooner and therefore are hotter a little longer.
  • matrixfan
    matrixfan Member Posts: 4
    Good news! I made a few adjustments over the weekend which are working well so far and I can say that the study radiator is now getting hot!

    1. Big mouth vent off the end of each return going up 16" and back 18" to hopefully avoid water getting in them.
    2. Shimmed the supply pipe in the study, to improve the horizontal run, and re-pitched the radiator accordingly.
    3. Installed a slower vent in the study
    4. Lowered the water level in the boiler
    1. 5-10 minutes for both mains to be hot from cold
    2. The water level in the sight glass is much more stable and never bottomed out.
    3. No geysers in the study
    4. 75 minutes to raise thermostat from 63 to 72 - Boiler fired continuously and did not build pressure until just before the stat was satisfied. Is this "good"? There are 4 large radiators in the living room and dining room where the stat is so I have them vented with #4s to give the upstairs a fighting chance with the much smaller radiators.
    5. LWCO but only just at the very end. I still have the auto feeder disconnected and after the winter I plan to replace the uni-match with a VXT so I can gain more control.
    During the remodel the radiator in the study was painted silver which I see is a no-no. I plan to paint it white when possible.

    I purchased and read We Got Steam Heat and am working my way through The Lost Art right now. Quite the rabbit hole but also fun to learn how this all works.
  • PC7060
    PC7060 Member Posts: 1,158
    edited December 2021
     During the remodel the radiator in the study was painted silver which I see is a no-no. I plan to paint it white when possible.”

    Silver paint is only a problem if it’s real metal based stuff.  Modern silver paint or powder coat is less unlikely to make a difference in my experience.
  • Jamie Hall
    Jamie Hall Member Posts: 23,276
    Sounds like you really got it, @matrixfan ! In answer to your question 4, in bold -- that's exactly how you want the system to operate. Perfect.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • dopey27177
    dopey27177 Member Posts: 887
    Installing a main vent in both steam mains, optimal location is at the the drop leg of the returns.

    If picture OMKGKFHY3A.jpg is the riser for the second floor a drop leg loop will cure your problem or make it work better.

    See drawing>

    This method of draining a single riser works well with one pipe steam.
    Basically what happens is all the returning water from the riser is diverted away from the steam main.
    Because the water no longer has to travel back to the boiler via the steam main the riser gets the full
    measure of steam needed for the radiator on the top floor.