Bosch water heater has power but does not ignite when hot water is opened; no error code displayed

Safety first: Turn OFF power and close water valves before removing filters or sensors.

• Verify multiple fixtures: Open two or more hot water taps fully to see if the heater starts. If it does, your normal flow may be below the activation threshold.
• Clean inlet filter: Remove and rinse the cold water inlet filter screen to improve flow.
• Check household pressure: If overall water pressure is low, consult a plumber to evaluate the supply or pressure regulator.
• Service flow sensor: Remove and clean the flow sensor turbine or paddle. Ensure it spins freely.
• Adjust minimum flow (if available): Some Bosch models allow adjustment of the minimum activation flow. Consult the manual to lower it slightly if your fixtures are low-flow.