... open, once water shut off, then gas solenoid valve auto close and alarm as well as display on touch screen, burner auto ... , if running ok, then gas solenoid valve open and ignition process, otherwise, valve close and no ignition process, if air blower is abnormally ... if running ok, then gas solenoid valve open and ignition process, otherwise, valve close and no ignition process, if smoke exhaust fan is ...