Utica Boiler Pilot light on but will not flame up!
I have a MGB150 with the EXACT same condition you describe. I think it is the transformer, becuase I tested for voltage at the gas valve with a call for heat, and i get millivolts only. I believe there should be at least 12 ro 24 volts there. I'm pretty sure 24V is correct. I stupidly replaced the gas valve, as I replaced an Aquastat a few years ago, and thought it would still be ok....I bet I'm wrong......I think Honeywell makes a lot of junk, at least that is what my experience has been. I've had problems with their SmartValve SV9500 series of gas valves in Perfection-Schwank furnaces as well. PLEASE let me know if you have figured out what the problem was with your boiler. Thanks.