R-Pro › Field cases › Refrigeration systems
Excessive frost buildup on evaporator
Likely causes
Defrost heater open circuit
Check: Verify defrost timer cycle duration
What to do: Verify defrost timer cycle duration → Measure defrost heater resistance (check for open circuit) → Test defrost termination sensor (thermal fuse) continuity → Check evaporator fan motor current and rotation direction → Visually inspect door gasket seal
Defrost timer or sensor malfunction
Check: Measure defrost heater resistance (check for open circuit)
What to do: Measure defrost heater resistance (check for open circuit) → Test defrost termination sensor (thermal fuse) continuity → Check evaporator fan motor current and rotation direction → Visually inspect door gasket seal
Evaporator fan motor failure
Check: Test defrost termination sensor (thermal fuse) continuity
What to do: Test defrost termination sensor (thermal fuse) continuity → Check evaporator fan motor current and rotation direction → Visually inspect door gasket seal
Door gasket failure (moisture ingress)
Check: Check evaporator fan motor current and rotation direction
What to do: Check evaporator fan motor current and rotation direction → Visually inspect door gasket seal
Refrigerant overcharge (suction pressure too low)
Check: Visually inspect door gasket seal
What to do: Visually inspect door gasket seal
Recommended: enter forced defrost mode and directly measure heater operating current
All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.
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