Lochinvar water heater attempts to light but shuts down quickly; display shows E002 and retries ignition several times.

Safety warning: Turn off electrical power and close the gas shutoff valve before removing burner or gas components. Do not attempt gas pressure adjustments without proper tools and training.

Steps to address E002:

• 1. Clean the flame sensor: Remove the flame sensor rod from the burner assembly. Gently clean the metal rod with fine steel wool or a Scotch-Brite pad to remove oxidation. Do not sand aggressively. Reinstall and ensure the sensor is fully in the flame path.
• 2. Inspect burner and orifices: Remove the burner assembly per the Lochinvar service manual. Check for debris, rust flakes, or spider webs in the burner ports and orifices. Clean with compressed air and a soft brush; do not enlarge orifices.
• 3. Check gas supply and valve position: Confirm the manual gas valve is fully open. If other gas appliances show weak flames, contact your gas supplier to check supply pressure.
• 4. Verify ground and wiring: Ensure the heater has a solid ground connection and that the flame sensor wire is not damaged or loose. Poor grounding can cause intermittent flame signal loss.
• 5. Test operation: Restore gas and power, then reset the unit. Observe ignition. If the flame lights but the unit still trips E002, the gas valve or control board may not be maintaining stable flame and should be tested by a qualified technician.