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Steam Boiler needing water

requiemdream6 Member Posts: 3
edited December 2020 in THE MAIN WALL
Hi all,

Need some help because I am at the end of my rope with my one-pipe steam system. I'm having to fill the boiler up every couple of days (depending on how cold it is). I have done everything I can think of. All air valves (including mains) have been replaced, valve stems repacked with graphite packing, watched for steam out of the chimney, boiler was drained and fresh water at the beginning of the year as well and checked every radiator for proper pitching. I have searched everywhere in the basement for any sign of leaks in the mains or branches but found nothing. There is also no buried return lines but one of the branches does go to a crawl space and the others are in the walls to go to the second floor, those obviously haven't been checked but i see no evidence of any water damage anywhere. I have yet to get under the crawl space but it was recently insulated with blown in insulation so I don't want to go ripping anything out unless i absolutely need to and the amount of the pipe in the crawl space is probably no more than a foot of pipe. My only thought is that either my boiler has a crack (but no water on the floor or anything) or maybe there is an issue with water getting back to the boiler and its sitting in the returns and evaporating? I do get a water hammer in one part of the system but i'm not sure which pipe is making the noise yet. The water hammer used to be very bad last year but since i have done all these other things described above, it's gotten so much better. I don't want to call in a plumber unless i have done EVERYTHING i can to resolve this on my own. I do not have an automatic water feeder which sounds like i need to get to limp through this winter.

I have not drained the return lines because there is not valve on the pipe, its just a plug and i'm scared to open it and let the possible sludge out and not be able to stop it. I suspect that because there is no ball valve on the return line drain that the returns have not been cleaned out in a long long time but at the same time i have no idea whether that will help this issue and i don't want to create more issues.



  • Jamie Hall
    Jamie Hall Member Posts: 22,900
    Well, the water is going somewhere. It doesn't just magically disappear.

    To track down where is a little pesky in cold weather, but here goes.

    First step: turn off the boiler and lower the water level to just below the bottom of the Hartford Loop. Put a make on the sight tube and come back as much later as you can before you freeze. Has the water level dropped? If so, there is a leak in the boiler below the water line.

    Otherwise, step two: warm the house up. Then turn the boiler off again, only this time fill it to just below the top of the sight tube. Check in 15 minutes and refill i necessary. Then again record the level and go away and come back as much later as you can and check the level. Has the water dropped? If so, there are two possibilities: either there is a leak in the boiler between the level you first marked in step one above, or there is a leak in a wet return somewhere -- much more likely the latter.

    If it still hasn't turned up the leak has to be a steam leak, and it -- or they -- has to be above the top of the boiler sight glass.

    This is much harder to find when you still need the boiler to heat, as if it is in the boiler itself it may not be obvious -- the plumes of steam out the chimney test is pretty diagnostic, but not good if the air is drier or the leak isn't all that large. However, all is not lost.

    Is there a boiler drain with a hose connection on it? If so, verify that water can come out of that connection (just crack it open -- it should flow, if slowly) and then put a piece of hose on it. Raise the open end of the hose up to just below the level of the header (no higher!) and, having gotten the house warm again, turn the boiler off. Again. And fill the boiler until water just comes out of that open end of the hose. Go away as usual as long as you can. When you come back, is the water still just at the end of the hose? Or do you have to lower the hose down until water comes out? If you have to lower the hose more than half an inch or so, the leak is in the boiler (since you eliminated the wet returns earlier)(actually, there is a remote chance that it is in a drip rising from a wet return -- look around at every single one and see). This is not good, but at least you know. In any event, lower the water level back down to where it belongs, fire up and warm up the house (close that drain!).

    If the pesky thing still hasn't turned up, at least you have eliminated a lot of possibilities -- and all the expensive ones.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • requiemdream6
    requiemdream6 Member Posts: 3
    @Jamie Hall I very much appreciate your feedback! I will say that i have been watching the water level like a hawk and i only seem to lose water when the boiler runs. It stays consistent whenever the boiler is not running. I will try filling it up all the way to the top of the sight glass and watch the water level. Also, the floor is always dry and I've kept a close eye on the floor. In addition, the damper box on the back of the boiler has no plate of the bottom of it so i can lay on the floor and look up the flue pipe and i can feel the heat going up the pipe but i see zero moisture/Steam, not sure if thats important however. I have checked the chimney on multiple weather days to cover my bases and make sure there is not "atmosphereic" piece of the puzzle and i have never seen steam.
  • Jamie Hall
    Jamie Hall Member Posts: 22,900
    The problem is probably still in a vent or valve -- or even a drip from a rusting fitting somewhere. Even a small drip can add up to a gallon or two a week! The problem is finding it, as steam -- or even a drip -- may not show up as wet, since when it is happening things are nice and hot.

    Patience. It can really be frustrating.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • requiemdream6
    requiemdream6 Member Posts: 3
    So i filled the boiler up and was able to let it sit for about 3 hours (luckily these old house can keep their heat pretty well!) It only dropped maybe 1/2 an inch if that, picture attached. Top line is the starting level and bottom is where it ended up after 3-3.5 hours later. I saw no evidence of any leaks under or around the boiler. Is that drop normal? maybe the water cooling down could have caused that amount of drop? I can't figure out where the water would go.

    One note however, I filled it right up to the top so i had to open the spicket and drain a bit out and it was tough to get it to completely close so i had an minor drip into a bucket but couldn't have been more than a few ounces that dripped out over that period of time, dripped once every 30 seconds or so. I always have a bucket under that spicket in case of emergencies and its been bone dry for weeks so i know it doesn't normally drip out of there.

  • mattmia2
    mattmia2 Member Posts: 9,409
    if it is cold now you could wait another hour and see if it goes down another 1/3 of that
  • ethicalpaul
    ethicalpaul Member Posts: 5,584
    It should drop zero. That is, as long as the level was truly settled at the time you marked the top mark.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el