Sight glass full w/ rusty water

Old 12-01-06, 05:49 AM
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Sight glass full w/ rusty water

Recently I overfilled my boiler, which in turn caused the sight glass to completely fill with rusty water. I drained the boiler until the low water switch came on, but the water in the sight glass never reduced; it's filled top to bottom. Is there some incoming water that I don't know about that's keeping it full, even after I drained the boiler? I'm a new homeowner and all this stuff is foreign to me...

Are there any ways to drain the water from the sight glass? Is it possible that the valves got blocked by all the rust/crud?

Last edited by mmeisner; 12-01-06 at 12:46 PM.
Old 12-01-06, 04:27 PM
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Sight glass

When draining the boiler, the make up water should be turned off. It is possible the gauge is just stained. Some have a petcock on the bottom for draining just the sight glass. Obviously, the bottom gauge glass valve has to be closed during this process.
Old 12-04-06, 10:58 AM
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Ok, well it turned out that the sight glass was filled with a thick, iron sludge. I unscrewed the compression nuts, and carefully pushed the sight glass up a bit, and then out to the side, which allowed it to slip out from the top and be completely removed.

I cleaned all the sludge, as well as drained and ran water through the boiler. Hooked the sight glass back up and began filling. I was worried that sludge might be blocking the entrance to the sight glass, but it filled up just fine, and I can see where the water level is again.

Old 12-04-06, 08:14 PM
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Red face Dirty steam boiler

you need to blow-down the boiler every week, in a 5 gallon bucket. Drain and fill 1/2 way up the sight glass, and drain again. Do this several times. Then fire-up the boiler with a call for heat and keep the gauge glass about 1/2. Then shut it down and drain again, refill and fire up. If the waterline is jumping allover the place in the gauge glass, it's still dirty. You may need to do this for a few weekends till she clears up and remember to blow down the steam boiler once a week till the water is clear.

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