correct if the boiler fire's for water the boiler is ok, if you have 2 2port valves check to see if the c/h opens when the room stat is calling for heat, if the valve open but stil does not fire boile the valve needs replacing, if the valve doesnt open check you have 240volts to the valve if not check the room stat, if you have a 3port valve also check the room stat if that is sending power to the 3port, then the 3port is jammed or stuck, needs changing
baximan
September 2008