Display shows E03 and solution pump will not run; vacuum motors may still operate.

Safety: Unplug the machine and allow it to cool for at least 20 minutes before touching the pump area.

• Check for thermal overload: Many Prochem solution pumps have a built-in thermal protector. If the pump has been run dry or under heavy load, the protector may trip. Let the machine cool fully, then try restarting. If E03 clears after cooling, check for restricted solution flow (blocked filter or kinked hose) to prevent recurrence.
• Inspect pump wiring: Remove the side or base panel to access the solution pump. Verify that the pump connector is fully seated and that wires are not burned or broken. Repair or replace any damaged wiring harness sections.
• Test pump motor: Disconnect the pump and measure resistance across the motor terminals. An open circuit indicates a failed pump motor or thermal protector. Replace the complete Prochem solution pump assembly if open.
• Check for seized pump: Try rotating the pump shaft (if accessible) with a screwdriver. If seized or very stiff, replace the pump assembly.
• Control PCB driver: If the pump tests good but E03 persists and the pump never receives voltage, the pump driver circuit on the control PCB may be faulty. Replace the control PCB.