Display shows E08 and machine stops heating; temperature reading may be erratic or show dashes.

Safety: Allow the heater and solution lines to cool. Disconnect power before testing.

• Inspect sensor wiring: Locate the temperature sensor on the heater outlet or solution line. Check the harness for cuts, abrasions, or melted insulation. Repair or replace damaged wiring.
• Check connector: Disconnect the sensor plug and inspect for corrosion or moisture. Clean with electrical contact cleaner and reconnect firmly.
• Measure sensor resistance: With the sensor disconnected, measure resistance across its terminals at room temperature. Compare to Prochem service specifications (typically a few kΩ). An open circuit or near-zero reading indicates a failed sensor. Replace the solution temperature sensor.
• Control PCB input: If a known-good sensor is installed and wiring is intact but E08 persists, the temperature input circuit on the control PCB may be defective. Replace the control PCB.