Gas water heater attempts to light but shuts down; display shows E02

Safety: Turn off gas and power before opening any burner compartment. Allow the heater to cool.

• 1. Observe flame: Through the sight glass, check that the burner flame is steady and blue when it does light. Yellow, lifting, or unstable flames can cause flame-sense errors.
• 2. Clean flame sensor: Remove the burner assembly. Gently clean the flame sensor rod with fine abrasive pad to remove oxidation. Ensure the ceramic insulator is not cracked. Reinstall and ensure the sensor is properly positioned in the flame.
• 3. Clean burner: Brush the burner surface and ports with a soft brush. Use compressed air to blow out dust and debris. Make sure all burner ports are open and not rusted shut.
• 4. Check ground connections: Ensure the burner assembly and flame sensor bracket have a solid metal-to-metal ground to the chassis. Tighten mounting screws and clean off rust where needed.
• 5. Gas supply check: Confirm the gas shutoff valve is fully open. If other gas appliances show issues, contact your gas provider. If only this heater is affected, the gas control valve may be failing to maintain flame and may need replacement.

If E02 persists after cleaning and verifying gas supply, contact a qualified technician to test the flame-sense microamp signal and the gas control valve.