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Sight glass leaking and empty - edited - new? Related issue?

Cto Member Posts: 13
edited January 2022 in Strictly Steam
So I did what the posters advised.  Back to my original problem...

So what started my knob turning is that the sight glass had been full to the brim for two days.  I tried to drain some of the water from the boiler and noticed no movement from the sight glass.  Both knobs were (and are now) fully open (turned to the left).  The sight glass water was clear (and green with some additive they put in as this boiler was put in last year) and even though sight glass water was full, it called for water. 

Now, after all the water from the sight glass dripped out (when I closed both valves unknowingly), I turned the knobs back and the water has returned to the very top and is brown.  Tried draining some and didn't move the level still. 

I've turned the boiler off for now as I feel like I can't be sure how much water is in it.



  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,007
    "Turned sight glass knob slightly and sludge water came out. "

    If you are talking about the black knob at the bottom, it should be fully open (Righty tighty, lefty loosey).
    that's the isolation valve for the sightglass. If it is shut, the sightglass will fill with waterover a period of time, same symptom as sludge clogging the bottom connection.

    Fully open and shut the valve a couple of times to see what you get for water level. Also, make sure the top valve is fully open; it probably is not clogged, but you can open and shut that too, just make sure when you are done that both valves are open.

    If you have a water leak at the bottom, you can carefully check to make sure the drain connection is tight. How long has this been going on? How much leakage do you get?

    JUGHNE Member Posts: 11,062
    Are both of the site glass valves fully open?
    Try this when the boiler is cool.

    Exercise the valves, especially the lower one.
    As you turn the handles watch the small nut behind the knob that it does not move.

    On the very bottom is a small drain plug to drain the sight glass down.
    With both valves off you can open this to drain the glass down as a test that the water is free flowing.

    Close the drain plug and open the valves.

    You should then see the water level come up.

    You could manually add some water to the boiler to insure that the sight glass is reading the true level.
  • neilc
    neilc Member Posts: 2,703
    those valves aren't so hard to take apart, and clean, and make sure they're truly open to the boiler,
    with the boiler off and cooled down, and drain it,
    use a small cresent, or channel locks, and unscrew the small brass packing nuts under the black valve handles,
    then unscrew the valve stop from the valve body,
    take a glass protection rod and poke into the open valve body, all the way into the boiler,
    do both valves,
    now start to fill the boiler with the valve still disassembled,
    you're gonna flush water out of the valve body so have a pail or bucket handy,
    as water level rises to the valve, continue to poke with the glass protection rod,
    as the water runs clear, stop filling, and reassemble the valve,
    now fill to the top valve and do same thing,
    set the water level back down to normal and start that boiler,
    known to beat dead horses