Electronic gas water heater will not ignite; display shows E01 and burner never lights

Safety first: Turn gas control knob to OFF, shut off gas supply at the manual shutoff valve, and disconnect power before working on the heater. Allow the unit to cool completely.

• 1. Power reset: Restore power, then turn the gas control to ON and attempt a reset per the user manual (often by cycling power or pressing the reset/temperature buttons). Observe if the igniter glows or sparks.
• 2. Inspect flame sensor: Remove the burner access cover. Locate the flame sensor rod near the burner. If it is sooty or corroded, gently clean it with fine emery cloth or a Scotch-Brite pad until shiny. Do not bend the rod. Reinstall and reconnect.
• 3. Check igniter operation: With the burner door reinstalled and sealed, restore power and call for hot water. Look through the sight glass: verify that the hot surface igniter glows orange or that a spark igniter is sparking. If there is no glow/spark, the igniter assembly is likely failed and should be replaced.
• 4. Verify gas supply: Confirm the manual gas shutoff valve is fully open. If other gas appliances work poorly, contact your gas supplier. If gas supply is good but the burner never lights despite a working igniter, the gas control valve/ignition control may be defective.
• 5. Burner and orifice: If comfortable, remove the burner assembly and inspect the main burner and orifice for debris, rust flakes, or spider webs. Clean with compressed air (do not enlarge the orifice). Reassemble with proper gasket and screws.

Call a professional if you smell gas, see damaged wiring, or the E01 returns after cleaning and replacing the igniter.