Controller Fault — Emergency Diagnosis & Repair

Recognising these signs early can prevent total product loss:

• Displayed temperature jumps or reads clearly wrong
• Plant short-cycling or not starting when it should
• Alarms firing with no actual temperature rise
• Buttons unresponsive or screen blank or frozen

Take these steps now, before our technician arrives:

• Do not repeatedly reset the controller — note what it displays before and after.
• Check the sensor probe is still firmly seated and not damaged.
• Confirm the controller has power and hasn't tripped.
• Call REYDS for controller diagnostics and re-programming or replacement.

Our technicians check each of these in turn to pinpoint the fault:

• Failed sensor probe — A drifted or broken probe feeds the controller a false temperature, causing wrong control actions.
• Relay failure — An internal relay sticks open or closed, so the compressor or defrost won't energise correctly.
• Software or parameter corruption — A power surge corrupts the controller's set points, defrost schedule, or hysteresis.
• Power supply damage — A spike or water ingress damages the controller's internal power, blanking the display.

REYDS tests the sensor against a calibrated reference, checks relay outputs, and re-programs or replaces the controller with a compatible unit. We restore all set points, alarms, and defrost schedules, then verify the plant cycles correctly across a full on/off and defrost cycle.

A surge protector on the controller supply and annual sensor calibration prevent the drift and corruption that cause false alarms and poor control.