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Newly installed steam boiler - sight glass is losing water.

astrosinfinity Member Posts: 1
edited December 2021 in Strictly Steam
I had my steam boiler replaced earlier this year. The sight glass is losing about an inch or two of water every two weeks without the heater being turned on. I have heat in my basement (pipes under floor) and the person who installed the steam boiler said he can install a valve to cut off the connection to the basement as he believes the leak is caused by one of the pipes under the floor and that by installing a valve, the sight glass would not lose water. An automatic water-feeder is installed.

What would the other reasons be for the sight glass to lose that much water? Bad installation?

I don't want to tear up my basement floor to find the leak so I would like to figure out the other possible scenarios first. If the valve to cut off heat to the basement is installed, would that eliminate the possibility that it is an underground leak?

Lastly, what is the danger of using the boiler with this loss of water? Can I still turn on my heat or is this something I shouldn't be doing? Thanks.


    EBEBRATT-Ed Member Posts: 15,516
    If you have a leak and are constantly adding water this will damage the boiler over tim. Excess new water brings new oxygen in with it which can cause corossion.

    If you have steam return lines under the floor that is the most likely spot to have a leak. That pipe would have to be disconnected on both ends.

    Many times a new pipe can be run on top of the floor and the pipe under the floor abandoned, depends on your basement layout.

    Or the pipe may be run on top of the floor and go underground for a short distance.
  • KC_Jones
    KC_Jones Member Posts: 5,736
    Do you have a heated floor, or just pipes under the floor?

    If it's just return pipes under the floor, the valve isn't going to fix anything. The steam will still go out into the system and leak under the floor. No matter how you look at this the piping needs fixed. That said @EBEBRATT-Ed recommendation of running them above the floor may be your best option to avoid tearing up the floor.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
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  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    Are those pipes under the floor in which you have heat a radiant floor? And if they are, are they fed from the boiler with a pump? If so, yes, get valves on there and shut them off and see if the problem goes away. Unlike a leak in a wet return -- which should be protected by the Hartford loop -- a leak in a radiant floor has the potential to drain the boiler. which you really don't want.

    In any event, if the boiler loses water when there is no heat on -- it's not steaming -- there's a leak somewhere below the water line, and it needs to be found.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Hap_Hazzard
    Hap_Hazzard Member Posts: 2,846
    edited December 2021
    If your boiler is piped correctly, you shouldn't be able to lose more than two inches of water from your boiler via the wet return, so you can get through the winter without fixing it, but it's too much to ignore beyond that. You can install a valve on the Hartford loop (the pipe that comes up from the wet return and connects to the equalizer with a close nipple, but you need to be sure this is open whenever you run the boiler. This will prevent the boiler from losing water through the wet return, but it won't keep the water that's in the return from leaking out, so it only solves half the problem. When you open open the valve to start the boiler, you'll see the level drop, and you'll need to add water before you fire it up. That's not all bad, because the best time to add makeup water is just before you start the boiler. Heating the water drives off the oxygen, and the steam will push it out the vents as it rises, but repeatedly adding makeup water can cause other problems. Steam systems are meant to operate as closed systems.
    Just another DIYer | King of Prussia, PA
    1983(?) Peerless G-561-W-S | 3" drop header, CG400-1090, VXT-24