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

Safety first: Turn OFF electrical power and shut off 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 plug 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 to Reliance’s temperature/resistance chart (commonly around 10kΩ at 77°F/25°C). A reading far out of range indicates a bad sensor.
• 4. Replace sensor: If resistance is out of spec or 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 gives E2, the thermistor input on the control board may be defective. Replace the main control board.

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