i have no gas solenoid ignition there is no voltage to the soleniod in ch mode or dhw mode .All stats test ok pump is running diverter valve switching all switches are ok pilot light on possible thermostat board any ideas?
The gas valve is in series with the c.h. overheat stat which may be open circuit. This appears to be mounted on the main heat exchanger but if unsure follow the wires from the gas valve they may be connected via round plugs.