Boiler Not Firing On System Boiler in HW Mode?

not to shour about this model of boiler but mack shour allboiler isolatoin valves are open check for three way valve or diverter valve opration check water flow sensor [usuley on top of cold feed] . three way valve usuley you can hear it motoring over and see leaver shifting.diverters can be alittle bit more tricky self contained and move with next to no noise .trust this may assist you.

dave m
December 2009