I went to turn on my boiler last night and it wouldn't start. I had to rpelace the batteries in the thermostat upstairs because the digital reading wouldn't stay on. after replacing the batteries, the thermostat worked fine. Would this have anything to do with the boiler not flaring up? I looked under the boiler and the pilot light is on. However, last year I have to constantly add water to my boiler becuase it keeps going below the water leavel and turning off. The water level valve is a bit rusted, but I can see the water level. Thansk for any advise.