GSW power vent water heater displays E009 and the unit locks out after several failed starts

Safety: Turn off gas and power before servicing. Avoid repeated manual resets without addressing the cause.

• Clean and inspect flame sensor: Remove and clean the flame rod with fine abrasive pad. Ensure it is properly positioned in the burner flame.
• Check igniter performance: Observe ignition (through sight glass) after restoring power and gas. If the igniter glows weakly or spark is inconsistent, replace the igniter assembly.
• Verify gas supply: Confirm other gas appliances operate normally. If flames are small or unstable, have a gas technician check inlet pressure and regulator operation.
• Reset control: Follow the GSW manual to clear lockout (often by cycling power or pressing a reset button). If E009 returns frequently, the control board or gas valve may require replacement by a qualified technician.