R-Pro › Field cases › Refrigeration systems
Defrost Timer / Controller Failure
Likely causes
Defrost timer motor failure or gear damage
Check: Mechanical timer: manually advance to defrost position; heater activating = timer faulty
What to do: Mechanical timer: manually advance to defrost position; heater activating = timer faulty → Electronic: force defrost cycle and check if heater activates → Measure defrost termination sensor (bimetal/NTC) resistance → Replace timer or controller with same spec → Verify defrost cycle and heater operation after replacement
Electronic defrost controller PCB failure
Check: Electronic: force defrost cycle and check if heater activates
What to do: Electronic: force defrost cycle and check if heater activates → Measure defrost termination sensor (bimetal/NTC) resistance → Replace timer or controller with same spec → Verify defrost cycle and heater operation after replacement
Temperature sensor (defrost termination) failure
Check: Measure defrost termination sensor (bimetal/NTC) resistance
What to do: Measure defrost termination sensor (bimetal/NTC) resistance → Replace timer or controller with same spec → Verify defrost cycle and heater operation after replacement
The defrost timer or controller is not executing defrost cycles normally. Replace it.
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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