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Rising Water level in steam boiler

Raj Member Posts: 10
My steam boiler has had rising water levels in the site glass x 2 weeks.  I have drained off water nearly every 24-36 hours despite having automatic water feeder shut off for 2 weeks.  I would think with water feeder off and only able to add water manually I should have been adding water by now rather than constantly draining off (level got so high one afternoon that it started pouring water out of first floor radiators.)  My oil contractor thought it was a problem with auto. feeder, so he shut off and said it should be fine.  My older/more experienced heating contractor thinks there is a leak somewhere in the connection from water supply to boiler that is leaking in water despite water feeder off and stop valves all in off position. 

As an aside when boiler was installed by previous homeowner they connected the boiler to receive its water from hot water side rather than cold side, so my contractor thinks the hot water may have ruined a stop valve and lead to leak.  He thinks we should re-pipe to cold side and change all valves--$600-700 repair.

Any thoughts on above and/or suggestions as to where water coming from would be appreciated


  • mysterious source of water

    the first step is to make sure where the excess water comes from. when you say the feeder has been shut off, are you referring to turning off the electric supply to the feeder, or to valving off the water supply to the feeder? only by cutting off the water supply, will you be sure.

    does this boiler supply hot water to the house as well? if so there may be a coil leaking under pressure into the boiler.

    whatever the source of the excess water, it should be stopped asap, before the excess oxygen causes more major problems!--nbc
  • Rod
    Rod Posts: 2,067
    Boiler Flooding

    Hi - There are generally only two sources for boiler flooding:

    1. The "make up" water line either manual or through the automatic water feeder.

    2. In internal coil which provides hot water for domestic use.

    Does your boiler have an internal coil to heat water for domestic use? If so this coil can develop pin holes leaks which results in the flooding of the boiler. If this is the problem, there are replacement coils available.

    If the problem is on the makeup water line then the automatic feeder and /or the valves will need to be rebuilt or replaced.

    - Rod
  • Raj
    Raj Member Posts: 10
    Rising Water Level in boiler

    The boiler does not warm the hot water, I have a separate natural gas hot water heater for that.

    With the stop valves to the auto feeder off, I do not see water level rising when the feeder tries to kick on (I didn't cut electrical supply to it,) so my assumption is that particular valve is ok, but one of the valves higher up the chain is bad.

    What other problem was the other replier referring to with respect to oxygen damage?
  • Raj
    Raj Member Posts: 10
    water level

    What kind of problems are you referring to with respect to the oxygen?
  • Raj
    Raj Member Posts: 10
    water level

    -so I valved off water supply

    -boiler does NOT heat hot water
  • oxygen damage

    fresh water contains a lot of oxygen, and this combination plus iron = rust. when the boiler is constantly firing in the dead of winter, the oxygen is driven off by boiling; however in the shoulder season, the burner runs less, and the freshly-added water contains more oxygen. the effects of this would not be noticed immediately, but towards the end of the life of the boiler, which would come sooner as a result. any fresh make-up water should be heated as soon as possible after its addition.

    most of us do not like auto-feeders for this reason. checking the water level, and blowing down the lwco, also forces us to inspect the boiler, on a regular basis.--nbc
  • Raj
    Raj Member Posts: 10
    water level

    -thanks for clarification and help

    -my plan is to to have auto feeder removed when I have what seems to be the inevitable re-piping and valve replacement work that needs to be done.
  • moneypitfeeder
    moneypitfeeder Member Posts: 249

    Do you have a manual valve in the autofeed line as well? If a manual valve is closed, but leaking it will overfill a boiler. (mine did, and since it was when we first moved in, and were not monitoring the boiler, it flooded my system to the 3rd floor of the house. Not a fun mess to clean up.
    steam newbie
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