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What do I do now that the tenant flooded the 1-pipe steam system?

After bleeding the 1-pipe steam system, the left water shut off remained open. The boiler was completely flooded as was the basement floor. The radiators were dripping water from the valves on the 2nd floor and there's staining on the ceiling on the 1st floor apartment. Is it possible they flooded the whole system? If the system continues to run, will the steam eventually push all the water back to the boiler and the system will fix itself? Or is there something else that needs to be done?


  • KC_Jones
    KC_Jones Member Posts: 5,739
    Did you drain the water back out? If you drained the water back to normal level in the boiler there really shouldn't be any water left in the system to be "pushed back" to the boiler. Where did all the water in the basement come from? Did it pop the pressure relief on the boiler? Was there enough water in the basement to get to the gas valve on the boiler?
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Fred
    Fred Member Posts: 8,542
    When you say "after bleeding the system" what exactly was being bled? There isn't anything on a typical one pipe steam system that needs to be bled. The water in the basement, did it come from the main vents?
  • 1920sMulti
    1920sMulti Member Posts: 2
    Thank you all so much for answering my question.

    To answer some of yours. They were flushing the boiler to get rid of some of the rust build up in the boiler and cleaning the site glass as stated by ww because the water was dirty.

    Yes, the water in the basement was pouring out of the overflow pipe (sorry still not good with the lingo yet) from the boiler. The tenants were taking bucket after bucket out the basement door to keep it from filling up the basement because they couldn't find the main shut off and thought they had turned off the shut off valve.

    The boiler fired up fine after we drained it to the 1/2 way mark on the site glass.

    So I'll check the gas valve on the boiler - what type of damage should I look for? Corrosion?

    The drain valve below the wet return or is it at the water line? When I talk about flushing the boiler I'm using a valve that is at the water line.

    I'll replace the air vents on the radiators just as a precaution, and check the shut off valve. It seems to be fine although a bit tight.

    We have had some hammer since, would it help if I pitched the radiators a bit more?

  • Fred
    Fred Member Posts: 8,542
    If you see any indication that water reached the gas valve, it should be replaced. Water can get into that gas valve and corrode from the inside potentially causing the valve to fail in an open position.
    Flushing the boiler out requires that you use the valve below the wet return. The valve at or slightly above the water line is typically the skim port and that is used whenever you have new pipe work or repairs done that might introduce oils to the boiler. oil will float on top of the water and must be skimmed off very slowly to stabalize the water in the boiler. You should not see more than 1/2 to 3/4 inch of bounce in the water in the sight glass.
    The water hammer may go away on its own after a day or two of use. If it doesn't, check all the radiators for proper pitch as well as the horizontal mains and horizontal radiator feed lines and make sure they don't have any sags in them and that they have some pitch to them. The weight of all that water could have possibly caused one or more of those to lose their pitch, especially if they were not properly supported. If the hammer continues, try to identify where it is coming from. That will give you a good indication of where to look for a pipe or radiator that may no longer have the proper pitch.
  • ww
    ww Member Posts: 282
    the drain valve is on the bottom of the boiler near the floor. take a garden hose and hook it to that and put it in the floor drain. if the boiler is cold leave the valve open and fill the boiler to clean it out some..watch the site glass...when it goes to the top of site glass that's enough..and shut water off and drain a bit more.

    i read somewhere in this thread the vents may be bad. they may be but if it were me i'd just try and rinse them out and put them back since i wouldn't want to buy new ones. don't know if that would work but i would try it before getting new ones to take a shot..maybe this won't help..or maybe it would...

    but usually they cost alot. if they were no good to begin with then i'd change them...providing you put the right ones in. just because the vent is in the radiator doesn't mean it's the correct one..if you buy new ones and they weren't right to begin with you will spend more. you can go over the procedures here on how to do that.

    how deep was the water filling the basement..if it didn't go above your heating appliance maybe nothing is wrong there..take a look...now if it was underwater..then that's another story.

    one of the responders told you the water may not drain out right away...and cause water hammer..don't pitch anything more yet...but take a level and see if they are pitched to begin with.

    one more thing...who caused this mess and what did they say..why did they touch anything to begin with and not know the basics of something as simple as this?

    the valve at the water line..it depends..that may be the fill valve..don't know..but the drain valve is on the bottom of boiler..usually a garden hose fitting with gate valve.