If the heater fails to light, the gas valve de-energizes for a 30-second blower post purge. The sequence retries three times until lockout (IF code) and waits 60 minutes before retrying. Ensure all connections and pressures are correct.

Check connections located on both the left and right side of the heater cabinet. Ensure low voltage, high voltage, and gas supply connections are secure. Verify the control hookup is located outside the control box.

Only qualified technicians should attempt repairs. Replace damaged wiring immediately and ensure the heater is properly grounded and bonded to reduce the risk of electrocution and electric shock hazards.

Ensure the voltage is within 10% of the required voltage. Verify both neutral and ground connections are clean and secured. If the connections are correct and the error persists, replace the ICB.

The control checks for an open blower vacuum switch, starts a pre-purge cycle, and checks for a closed blower vacuum switch. At proper ignitor temperature, a 4-second trial begins. The gas valve opens, and the flame is monitored. The blower operates...

Remove wires from the water pressure switch and measure continuity across the terminals while the pump is running. If open, replace the pressure switch.

Test continuity across the exhaust gas limit switch. If open, replace the switch. If the switch does not exist and the problem persists, contact support.

Verify that the installed flame sensor is 5 inches. If a 3-inch sensor is installed or if the sensor is damaged, replace it with the 5-inch version

Inspect gas orifices and burners for blockage. Clean as required. If damaged, replace the components. If not damaged and the problem persists, contact technical support.

Isolate the blower vacuum switch and measure continuity between switch terminals. If continuity exists, replace the switch. If the blower continues to run with the heater off, replace the ICB.