My Burnham Series 2 has suddenly decided to randomly extinguish the flame/pilot. I replaced the thermocouple but no change. I checked the flue and it's clean, altho I don't believe the blocked flue switch kills the pilot, merely prevents the boiler from doing anything but pilot. Today I came home to find the boiler dead again, and I noticed the damper was open. This leads me to believe the boiler is dying when heating, or when attempting to fire up. I'm unsure what else could be wrong.