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Water Loss

Hello all:

Let me first say that I am new to steam systems, so please excuse my lack of proper lingo.  I asked my first question on this forum a few weeks ago and received a few great, helpful responses. After that, I bought Dan's book "We Got Steam Heat" and read it cover to cover overnight - very informative! I consider myself extremely lucky that I found this website.

Okay, with that said, let me throw this off you guys and gals... I have two steam boilers (for a two family house). I (so far) haven't had any problems with my (second floor) heat, though I haven't been running it much at all yet. But the tenants' system (first floor), shuts off every 7-10 days or so because of low water level. (The tenants use their heat quite a bit.) I "flush" the low water cut-off weekly (letting the water flow until clear; maybe emptying about a quart). Other than that, I don't see any water leaking anywhere, and the tenants aren't complaining about spewing water from the radiators or anything like that.

(Also, as it may be relevant, I should note that I had the boilers fully serviced about 2 weeks ago.)

My question is: is it ordinary to lose enough water every 7-10 days so that the low-water cutoff kicks in and shuts down the boiler? After this happens, I usually slowly fill the boiler so that the water level in the gauge glass is a little less than 2/3 full. About 7-10 days later, the water level is low again.

Any thoughts? Your help is, as always, much appreciated.


  • BobC
    BobC Member Posts: 5,182
    Excess water use

    What kind of boiler is it and how old is it? Is there any banging in the pipes and does it change over the 7-10 days? does the system heat all the radiators ok? On a mild day it's normal to just get partial heating of radiators.

    When the boiler is firing and actively making steam, check the chimney to see if there is a lot of white smoke, that could indicate a hole above the waterline. If you do see a lot of steam coming out of the chimney try flooding the boiler when it is cool to see if any water seeps out, it may take a while if it's a small hole. After the test drain the boiler till the water level is normal.

    There could be a plugged return line but that would usually cause the boiler to empty faster. Post some pictures of the boiler and the near boiler piping.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • JHill33
    JHill33 Member Posts: 5
    Water Loss

    Thanks so much. I'm at work, but will answer your questions (I think I know the installation year but want to make sure) and post the requested pictures as soon as I get home. I'll also check for the white smoke and let you know!
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