I'm a renter in Boston getting ready to get the boiler started for the season. I have an old gas boiler that will fire up but not pump heat through the pipes/radiators. My sight glass window is full. I have drained it until the auto fill comes back on, and it fills the sight glass all of the way again. I'm not really sure of what I'm doing here, so I'm just looking for a little advice. Am I correct in assuming my sight glass should be 1/2 to 2/3 full? Should I keep draining the system to clean my auto-fill mechanism of debris? Should both knobs (on top and bottom of sight glass) be open? Thanks in advance,
There's a valve just below the sight glass. Every month you need to drain a gallon or so off to keep the top off system working properly. The sight glass should be readable on the sight glass, you should be able to determine the level of the boiler, so anywhere between 1/3 - 2/3 full.
It sounds like the boiler is too full and and not generating a lot of steam to heat to radiators.