Rug Doctor digital carpet cleaner shows E8 and the solution pump cycles on and off rapidly or will not run steadily.

Safety: Turn off and unplug the unit before removing tanks.

• 1. Check solution tank: Ensure the clean water/solution tank is filled and fully seated. Press down firmly until you hear or feel it lock. Verify the tank cap and valve are installed correctly.
• 2. Inspect inlet screen: Remove the tank and check the inlet screen or filter where the tank mates to the base. Clean any debris or scale buildup with warm water and a soft brush.
• 3. Flow sensor cleaning: Some models use an in-line flow sensor or turbine. Access it by removing the base cover. If accessible, disconnect and flush it with warm water to remove residue that may prevent it from spinning or sensing flow.
• 4. Wiring check: Inspect the harness from the flow sensor to the control board for pinched or broken wires. Reseat connectors.
• 5. Replace sensor if needed: If the tank is full, lines are clear, and wiring is intact but E8 persists, replace the flow/low-water sensor assembly.

Tip: Avoid leaving solution to dry in the machine; flush with clean water after use to prevent sensor fouling.