Burnham water Boiler (home heating system)?

I am a Plumber in Boston, first thing I do on a no heat call is turn the thermostat all the way up and see what happens. There are a few reasons the main burner flame may cut out quickly. One is the Thermostat is set to close to the room temp. Another reason could be the Boiler is already at it max temprature. Without seeing it I can't say what it should be at but on a Burnham maybe 180 or 190 if you have baseboard or radiators. Unles it is the Revolution I think which is the one with the corners angled so it isn't quit square. That boilers High limit is 210 . Inside the front of the boiler is a temp pressue guage ,probably on the upper left . (Revolution is hard to see in the upper right) . If the water temp is hot you probably have a circulation problem.