Assess the causeFollow the evidence.
Use the exact model and code to identify the monitored system, then check its sensors, connections and components.
The exact model and operating conditions determine which tests apply. These are possible inspection directions, not a list of components that must be changed.
Before the appointmentKeep the useful details.
Photograph the complete display or record the blinking sequence before a reset clears it.
Record the timing, previous work and accessible model label. Do not remove covers or handle live, refrigerant or pressurised components to obtain information.