Diagnosis
The water pump is not activating, or the flow path is blocked. Verify the tank's valve is open and the internal tubing is connected.
How to Fix It
Confirm the tank's slider switch is in the 'Open' position (line aligned with the arrow). Remove the tank. Tilt it over a sink and open the valve. Water must flow freely. On the robot, inspect the rubber inlet seal in the tank bay for tears. Reinstall the tank and start a cleaning cycle. Listen for a faint hum from the pump area near the tank bay.
If That Didn't Work
Mineral deposits have clogged the pump or the internal drip nozzles above the pads. Fill the tank with a 50/50 mix of white vinegar and water. Run the robot in a contained area (like a shower) for 10 minutes to circulate the solution. Then flush the system with clean water.
Heads Up
The pump is a non-user-serviceable part. If cleaning does not restore flow, the pump assembly must be replaced.