Display shows E18 and the unit cycles the pump rapidly without delivering consistent spray.

Safety: Unplug the unit and remove the solution tank.

• Prime the system: Refill the tank and run the unit while holding the trigger for 30–60 seconds to remove air from the lines.
• Clean flow sensor: Access the flow sensor (often a small plastic module with two hoses and a wire harness). Remove it and flush with warm water to clear debris from the turbine.
• Check turbine movement: Gently blow through the sensor and listen for the turbine spinning. If it is stuck, soak in warm vinegar to dissolve limescale, then rinse thoroughly.
• Test sensor output: With a multimeter set to DC voltage, spin the turbine and check for pulsing output from the Hall sensor (advanced users). If no signal, replace the flow sensor assembly.