--108.50.xxx.xxx

A plumping supply store may have sodium fluorescein dye. It dyes water a bright green color. --76.35.xxx.xx

Thanks Rick, that's a good idea. I use dye to check for toilet flapper leaks and I'll bet it'll work well for the steam leak. --108.50.xxx.xxx

Some gas boilers are a sectional boiler where the leak maybe seals between each section. If fresh water is constantly being added there is oxygen where that will corrode the entire heating system. Steam heating here is very rare where forced hot water is more common. Some sectional boiler are known for leaks between the sections as the seals go bad. Eventually it maybe better to go to forced hot water where install a new gas boiler then use uponor pex heating pipe to connect up copper finned convector radiators. Where forced hot water is more efficient as operates on lower temperatures. A type pex is easy to work with where bends easily then the expense is lower. --216.110.xxx.xxx

My mom's boiler has lasted over 40 years. We keep the sight glass full to a half inch from the top even though the service tech says keep it lower to make it easier to make steam. I believe there is less rust because less of it is exposed to air. Have always had to fill it weekly. There is corrosion in the pipe that goes to the blow off valve on the boiler. you can't see it because the pipe is covered by the boiler housing. It leaves no wetness because it's so hot. It's so old I'd be afraid it would have a catastrophic break at the boiler. Less risky to leave it be. If this was in a rental I'd be inclined to add an automatic feed. --172.56.xxx.xx

My mom's boiler has lasted over 40 years. We keep the sight glass full to a half inch from the top even though the service tech says keep it lower to make it easier to make steam. I believe there is less rust because less of it is exposed to air. Have always had to fill it weekly. There is corrosion in the pipe that goes to the blow off valve on the boiler. you can't see it because the pipe is covered by the boiler housing. It leaves no wetness because it's so hot. It's so old I'd be afraid it would have a catastrophic break at the boiler. Less risky to leave it be. If this was in a rental I'd be inclined to add an automatic feed. --172.56.xxx.xx

My mom's boiler has lasted over 40 years. We keep the sight glass full to a half inch from the top even though the service tech says keep it lower to make it easier to make steam. I believe there is less rust because less of it is exposed to air. Have always had to fill it weekly. There is corrosion in the pipe that goes to the blow off valve on the boiler. you can't see it because the pipe is covered by the boiler housing. It leaves no wetness because it's so hot. It's so old I'd be afraid it would have a catastrophic break at the boiler. Less risky to leave it be. If this was in a rental I'd be inclined to add an automatic feed. --172.56.xxx.xx

Last question. What steam pressure does the system operate? --184.57.xxx.xxx

I've got a 5psi gage and with usual operation, the needle never moves off zero. If I turn all the thermostatic valves to zero, I can get the pressure to 2psi, the cut out pressure. --108.50.xxx.xxx

Recently I took an IR camera through the house, along with a moisture meter, but couldn't find anything unusually, though I'm not sure what exactly I'm looking for with the IR camera --108.50.xxx.xxx

Small Potatoes, I am leaning towards an autofill, but it would be real nice if I can find the leak. Thanks. --108.50.xxx.xxx

I just had an expansion tank get gunched up so it wouldn't fill so I had no return pressure in the loop. It looked like there was a small leak somewhere - and there might still be a small drip in a bleed value, but with two small issues, the problem looked bigger --174.131.xxx.xx

Thanks Ray-N-Pa. Sound a little like what Jim said about several steam vents adding up to all my water usage. --108.50.xxx.xxx

For me, once a year, I need to have someone look at the boiler. This one is a 1984 so it is about time to replace it - but I keep on saying, just one more year. --174.131.xxx.xx

Wow, 40 years for the boiler. I'll bet having someone look at the boiler once a year has gotten you that life. Of course, who knows..but? --108.50.xxx.xxx

Cast iron sectional boilers have a long life where less stress if using forced hot water as operate a lower temperature along can add Spirovent air and dirt separator which eliminates air and separates black sludge. It is difficult where only power vented gas boilers that combustion air from outside then vent directly through the wall have higher efficiency numbers. Higher efficiency gas boilers are more suitable for hot water radiant heating as heat is evenly distributed where can add more insulation to walls. I bought two 300,000 Btu Slant Fin gas boiler with intermittent ignition and vent dampers. Slant Fin gas boilers use better sealing for sectional boilers which is less likely to leak. All steel between sections. --216.110.xxx.xxx

Good luck, Jim. --184.57.xxx.xxx