The past two years, early in the heating season, I am getting a loud buzzing noise from my boiler, which seems like it is coming from the electronically controlled natural gas valve. The unit is a Slant Fin 90,000 BTU hot water boiler.
From what I have found online, the buzzing could be...
....by Honeywell. If you didn't know, they can be changed without turning the water off. I know many people on here don't like to replace gas valves due to tank issues. I will try to load some pics.
These show the back plate that stays in the heater with dry well and the sensor.