Sime water heater locks out with E02; burner lights briefly then shuts down within a few seconds.

Safety: Switch off power and close the gas valve before opening the casing. If you notice strong gas smell, do not relight; call a gas technician.

Steps:

• Check gas supply stability: Confirm other gas appliances are not causing pressure drops (e.g., multiple large appliances running simultaneously). If gas supply is intermittent, contact your gas provider.
• Clean burner and combustion chamber: Remove the burner cover. Vacuum dust and debris from the burner and heat exchanger fins. Ensure all burner ports are clear.
• Inspect flame electrode: Clean the ionization electrode with fine abrasive pad. Check the cable for damage and ensure a tight connection to the control board.
• Check flue and air intake: For room-sealed Sime models, inspect the concentric flue terminal outside for obstructions (leaves, nests, ice). A blocked flue can cause unstable flame.
• Test operation: Reassemble, restore gas and power, and run hot water. Observe if the flame remains stable. If the error returns, the gas valve modulation coil or control board may be defective.

Professional help: Gas valve pressure and modulation checks must be done with proper manometers by a licensed technician. If E02 persists, schedule service.