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Dirty Water in Sight Glass

Jeff_44 Member Posts: 94

At the beginning of the heat season I now have dirty water in the sight glass.

Have not had this before. Do I skim the boiler or drain from the bottom?

Also notice a little more bounce in the water level than we've seen before.

Thanks as always for your help.


  • BobC
    BobC Member Posts: 5,473
    drain or skim

    How old is the boiler?

    Has any work been done to the system since it was turned off?

    Is the water just a light rust color or is it really dark?

    How much bounce is in the sight glass when the boiler is making steam?

    All boilers rust to some extent. You should always bring a boiler up to steam after adding water to drive any oxygen off, oxygen in water accelerates rust. If the water is filthy the boiler should be drained and refilled with fresh water, there should be a drain valve near the bottom of the boiler. You may have to do it a couple of times if it doesn't imporve after a single emptying. After your happy with the way the water looks you have to run the boiler up to steam and drive off the oxygen.

    Bouncing in the sight glass can indicate skimming is required. If it looks like there is oil in the water the boiler has to be skimmed to float the oil of the surface of the water. Some dirt and rust in the water usually won't matter but a little oil can interfere with a steam boilers operation. Skimming takes hours because you want to allow the water to very slowly trickle out, the slower the better. Does the boiler have a skim port?

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Jeff_44
    Jeff_44 Member Posts: 94

    The boiler is 7 years old. No work has been done since last year except an annual cleaning (burners). I did add one 90 to one of the mains for work I'm going to do later, but I noticed the dark water before I added this EL. The water is quite dark and there is more bouncing than normal. I read the manual and it cited skimming as the way to clean the boiler. I do have a drain valve and skim port. I skimmed the boiler before and yes, it did take hours - this was about six years ago.
    STEAM DOCTOR Member Posts: 1,929

    Start off by filling and draining from bottom 2 or 3 times. This is something you should do before the beginning of every heating season anyway. Fire up the boiler after the final fill and watch water line
  • Jeff_44
    Jeff_44 Member Posts: 94
    Thanks for your help

    Will do as suggested.

    This is a great site with lots of great folks helping out.

    Thank You.
  • ChrisJ
    ChrisJ Member Posts: 15,451

    If you added any fittings to the system there is a chance you introduced oil.  Your bouncing water line also indicates this.

    Now, you could skim for a few hours, or days.  But I recommend using a wand.  Have a look at this thread and you'll see pictures of the wand I made.


    It is much faster than skimming and pretty much guaranteed to give you a clean oil free boiler in the end.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • Jeff_44
    Jeff_44 Member Posts: 94
    Draining and filling

    I let the boiler cool and then drained and filled it multiple times until the water came out clear. As soon as I let it come to steam there was dirty water in the glass again. Skimming may be next. I'm adding a new tie-in to one steam main so will wait till after I finish this work before I skim. Luckily, it's still quite warm here in NY so we have a little time before the cold hits.

    Thanks for all your help.
  • ChrisJ
    ChrisJ Member Posts: 15,451
    Same problem

    That is the same exact problem I was having which lead me to using a wand to wash the boiler out.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
  • VA_Bear
    VA_Bear Member Posts: 50
    How soon does the water show garbage after it starts to steam?

    If the boiler flushes clean and the garbage comes back after the condensate starts to return. your problem is in the condensate pipes and boiler flushing will not take care of it by itself. Until the pipes are cleaned or replaced, the garbage will keep coming back. Can anyone suggest a cleaning process or treatment for the condensate piping?

  • Jeff_44
    Jeff_44 Member Posts: 94
    Not too long

    The water is clear at first and then elements begin to 'float' into the water. It takes maybe 10 minutes before the water is murky. I cleaned the wet returns before I cleaned the boiler. I installed a valve at the top of the drips as they return into the wet return. There are two valves at the end of the wet returns - one just before the hartford loop and one about 12" before that. I close of the first one and open the second. I then hook up a hose to the valve at the drip connection and run water through till it's clear. I do this every year at the beginning and end of the heat season.
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