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Replacing sight glass easy enough for steam newb?

Volldampf Member Posts: 17
Good Morning,

The sight glass on my boiler is cracked and while it's still holding on, it is dripping water and has also started to spray three thin fountains of water through my basement.

I am an absolute newbie when it comes to these steam things, but this looks easy enough to replace, I am thinking close the valves on the bottom and top, looks like there the two nuts to unscrew and then the whole affair should somehow come out.

Is this easy enough? What can go wrong here? Is it OK to take the glass out and trek to the nearest plumbing supply store with all the parts so that I can be sure I buy the right replacement glass and probably some seals that go in there? Or should I better call in a pro at this point? Can the boiler be left alone without the sight glass, with those two valves closed, while I am out to get the replacement parts?




  • Chris M_2
    Chris M_2 Member Posts: 67
    Site Glass Replacement

    It's easy enough to do.  Yes.. Close both the upper and lower valves. Loosen the nuts. Slide the nuts, along with the rubber gaskets and metal washers towards the middle of the glass, and you'll be able to lift the glass up a bit to make room to pull the lower end away from the lower seating.  Make sure that when you get the new glass, you get it cut to exactly the same length as the old one, and it's a good idea to replace the rubber and metal washers as well (although I've removed my site glass about 10 times to clean it and put it all back with the same washers).  You can safely run the boiler without the site glass temporarily, but get that glass back on there ASAP; you don't want to be running that boiler for too long without a view to where your water level is.
  • Volldampf
    Volldampf Member Posts: 17
    Sounds good

    Thanks for your encouraging response, Chris.I'll attack this over lunch.

  • Volldampf
    Volldampf Member Posts: 17
    Well, this was easy!

    The trickiest part of putting that new sight glass in was that the first plumbing store I went to had the glass and mounting hardware, but not the tool to cut it down to the right length and I had to go to another store where they were nice enough to cut it for me.

    Now new glass is in and I think of what needs fixing next on this thing.

  • turbobike
    turbobike Posts: 28
    sight glass

    biggest issue I found with sight glass (besides extreme difference in prices between dealers) is getting it cut. Best i could find was big $$$ for someone to cut it.

    So I bought 2. I learned to cut on the first one, and, after finding out how NOT to do it--I cut the 2nd one perfectly.

    I later found a cutting tool at Lowe's. If you're staying in your home for a long time, then the cost of the cutting tool will be recouped after 2 or 3 glass replacements.
  • Brad White
    Brad White Member Posts: 2,393
    Of course now that it is done...

    I am reminded of a tip my friend Norm Harvey taught me, to put a tight-fitting o-ring on the sight glass and roll it to the water level as a quick but adjustable visual indicator. Simple, cheap and very helpful.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"

    -Ernie White, my Dad
  • Volldampf
    Volldampf Member Posts: 17
    edited March 2011
    A different meaning of

    About the cutting, it was funny, I drove over to the second plumbing supply store after calling them first to make sure they could do it.

    The guy used a sort of plier looking thing with longs arms where the one arm with the little cutting wheel went inside the glass tube to score/cut it and the other arm rested against the tube from the outside with a little fork-shaped attachment. Well, turns out that tool didn't cut it! The tool was brand new out of the box,  but the new sight glass I had was just too thick for it.

    Who actually did do it was a *customer* at the store, a plumber who just went out to his truck to get his own cutting tool, an ancient looking thing looking like pliers with a cutting chain that went around the outside of the tube.

  • Volldampf
    Volldampf Member Posts: 17

    Good suggestion, Brad.

    I used some electrical tape on those rods that protect the sight glass.

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