I usually keep the water level in the glass tube at 3/4. That's where the fill line is. But now, the glass tube is completely full. I drain the boiler for a while but the tube does not empty but rather the low water level light goes on (so not to run the boiler without water).
When heat kicks in, the boiler gets pretty loud. Much louder than usual. I can hear rumbling in the pipes leading out of the boiler to the radiators.
I plan on calling the gas company to have a basic check up anyway, but does this sound familiar to anyone?