Reliance water heater displays E2, and the burner or elements will not operate.

Safety first: Turn OFF electrical power and shut off the gas (if gas-fired). Allow the water heater to cool before touching any sensor or piping.

Steps to check:

• 1. Inspect sensor wiring: Remove the access panel and locate the outlet temperature sensor (usually on the hot water outlet or tank top). Check the harness for cuts, burns, or loose connectors. Reseat the connector at the control board.
• 2. Check sensor mounting: Ensure the sensor is fully inserted into its well or clamped firmly to the outlet pipe as designed. A loose sensor can read incorrectly.
• 3. Test resistance: With power OFF and wires disconnected, measure the sensor resistance with a multimeter. Compare it to Reliance’s temperature/resistance chart (commonly around 10kΩ at 77°F/25°C). A reading far outside this range indicates a faulty sensor.
• 4. Replace sensor: If the resistance is out of specification or the wiring is damaged, replace the outlet temperature sensor with the exact Reliance part. Route the new harness away from hot surfaces and sharp edges.
• 5. Inspect control board: If a known-good sensor still results in E2, the thermistor input on the control board may be defective. Replace the main control board.

Warning: Do not bypass or jumper temperature sensors; doing so can cause overheating and serious safety hazards.