Error 08; water heater does not respond to hot water demand or heating request.

Safety: Turn off power and close the cold water isolation valve to the heater before opening any water connections.

Steps:

• Clean inlet filter: Remove the cold water inlet filter/strainer (usually at the cold inlet union). Rinse under running water to remove debris and reinstall.
• Check flow switch movement: On models with a mechanical flow switch, remove the switch body and ensure the paddle or piston moves freely. Clean off scale and debris.
• Inspect flow sensor (turbine type): For turbine sensors, remove the cartridge and check that the turbine spins freely. Descale gently if necessary.
• Check wiring: Ensure the flow sensor connector is firmly attached to the PCB and that there are no broken wires.

Note: If the heater still does not detect flow after cleaning and checks, the flow sensor assembly may need replacement.