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Junk in sight glass

Our steam boiler installer will be here shortly to skim and flush again. I've noticed that since the last skim session the pressure gauge never moves, and the low water cutoff LED goes on and off even though there's an inch and a half of water visible in the sight glass. Is it possible these controls need to be cleaned out. Also, the high pitched whine has become intermittent and changes in pitch.


  • Pumpguy
    Pumpguy Member Posts: 659
    It is possible that the top and bottom shutoff valves to the sight glass are closed. If closed, the level will not reflect the true boiler water level. Try opening and closing these valves and see what happens.

    It is also possible that the water passage in the bottom fitting has become clogged. If it has, it will be necessary to turn off and drain the boiler to below the level of this fitting before the fitting can be removed and cleaned.
    Dennis Pataki. Former Service Manager and Heating Pump Product Manager for Nash Engineering Company. Phone: 1-888 853 9963
    Website: www.nashjenningspumps.com

    The first step in solving any problem is TO IDENTIFY THE PROBLEM.
  • Gordo
    Gordo Member Posts: 857
    I would also recommend a "proper" valve on the bottom of the sightglass.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • Fred
    Fred Member Posts: 8,542
    @Msil1955 , Do you have a Cyclegard Low Water Cut-off? If so, it will shut the boiler down every 10 or 15 minutes to check the water level. That's normal for that abnormal Low water Cut-off.
  • Msil1955
    Msil1955 Member Posts: 12
    It's a Safgard. I've seen it run for longer than 20 minutes and the only time it shuts down is when the water level is 1 inch below the sight glass.
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
    Gordo said:

    I would also recommend a "proper" valve on the bottom of the sightglass.

    I installed the street 1/8th inch elbow and a 1/8 ball valve on your recommendation, @Gordo and I'm loving it!! No more scalded fingers!
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el