External chemical dosing pumps (detergent/rinse aid) do not run; no chemical drawn from containers.

Safety first: Wear appropriate PPE when handling commercial chemicals and disconnect power before wiring work.

• Check chemical levels: Ensure containers are filled and suction tubes are fully submerged.
• Prime lines: Use the machine's priming function or manually run the pumps to remove air from the lines.
• Inspect tubing: Look for cracks, leaks, or blockages in suction and discharge tubes. Replace tubing if degraded.
• Test pumps: Apply power to each dosing pump (technician only) to verify operation. Replace faulty peristaltic dosing pumps.
• Check control signals: Verify that the dishwasher sends a signal to the pumps during wash and rinse phases. If not, the control board or dosing module may be defective.