Navien unit shows E032 and stops; often related to water flow sensing.

Safety: Turn OFF power and close the cold water inlet valve before servicing.

Steps:

• 1. Clean inlet water filter: Locate and remove the cold water inlet filter screen at the bottom of the unit (if equipped). Rinse under running water to remove debris and reinstall.
• 2. Exercise flow sensor: The flow sensor is typically located on the cold water inlet manifold. Remove it according to the service manual and check for scale or debris on the turbine. Clean gently with water and a soft brush.
• 3. Check wiring: Ensure the flow sensor connector is firmly attached to the main PCB and that the cable is not damaged.
• 4. Test operation: Restore water and power, then open a hot water tap. If the unit still does not recognize flow and E032 returns, the sensor may need replacement.

Replacing the flow sensor is usually straightforward but should be done carefully to avoid leaks. If unsure, contact a professional.