I've got a single pipe steam system, 5 radiators, and a Burnham boiler that was installed in 01, with a Bock indirect water heater.
I've had no problems with it since I bought the house in 07. Water level has been very constant. It does not have an auto-fill, but obviously has a LWCO.
This morning I woke up to my pipes clanging like mad, which they have never done. Went downstairs and shut off the boiler, and the water level was over the top of the sight glass. I drained out probably 5 or 6 gallons to get it down to the proper level again, and watched it for a bit. I figured maybe the fill valve got some kind of schmutz in it or wasn't closed all the way, so I opened/reclosed it. After a few hours, it looked like the water level had crept up another 1/8" or so. (Boiler switch had been on, but it had not fired.) so I drained again back down to the recommended fill line and realized there was a secondary ball valve on the fresh water fill line back behind the boiler, so I closed that too, to hopefully figure out if it was the normally-used fill valve that was leaking.
Now, I have VERY rarely known 1/4 turn ball valves to go bad, so I find it odd that the fill valve would just suddenly decide to start leaking......
It also occurred to me that maybe it could be getting in from the hot water tank? I guess maybe if there was a leak in the coil that goes into the boiler, that would cause water to enter the boiler, but that, too, seems unlikely since this is all fairly new equipment (relatively speaking).
Anyone have thoughts on what the most likely culprit is? I have a service guy coming tomorrow to check it out, but I figured if I can prepare myself with any relevant data to give him that would be good.
I'm going to continue to watch the water level with both ball valves on the fill line shut off. Assuming it's unlikely that BOTH valves failed, if the water level goes up, that would point to the hot water coil?
If it is that, how much damage am I looking at price-wise? (Or is it something I could do myself?)
Sorry for the huge post, just wanted to give as much info as I can. You guys are great.