Bosch water heater displays E8; unit may start then shut down quickly

Safety first: Turn OFF power and close the gas shutoff valve. If you smell gas, ventilate the area and do not operate electrical switches; contact your gas supplier or emergency services.

• Check wiring to gas valve: Remove the front cover and locate the gas valve assembly. Inspect the electrical connector for secure fit and signs of corrosion or heat damage. Reseat the connector.
• Verify gas type and pressure: Confirm that the heater is configured for the correct gas type (NG or LP). A licensed technician should measure inlet gas pressure and adjust the regulator or supply as needed.
• Inspect for contamination: Look for signs of water or oil contamination in the gas line near the heater. Contamination can damage the gas valve and must be corrected by a professional.
• Test operation: Restore gas and power, then run hot water. If E8 persists, the gas valve or control board is likely defective.
• Professional replacement: Gas valve replacement and combustion adjustment must be performed by a qualified Bosch service technician to ensure safe operation and proper combustion.