From page 13 of said manual: "If a flame cannot be established within the trial for ignition period, the control will stop the flow of gas. The control will continue to energize the blower (interpurge) and attempt ignition again. If a flame cannot be established after three attempts, thecontrol will lock-out. A red LED light on the control will flash continually indicating a lock-out condition occured. Unplugging the 120VAC power supply to the water heater then restoring power will reset the control. NOTE: The control will perform a self-diagnostic check upon start-up and the LED will flash 3-4 times. During normal operation the LED remains off. A solid red LED indicates that the control must be replaced." As we say in Quebec - Voila !!!!!