What it means
A configured analog input is reading abnormally high in a way that indicates a sensor or wiring problem.
This entry is tied to the exact STS message family documented by Sullair. The same words can mean something different on another controller generation, so confirm the displayed message and machine documentation before acting.
Likely causes
- Pressure transducer, temperature probe or other analog sensor failure
- Open/short/wiring fault in the sensor circuit
Operator-safe first checks
- Record the complete message, including the channel number or name after AN_.
- Compare the displayed value with other available machine indications without opening the cabinet.
Trained maintenance / service checks
- Inspect sensor wiring and connections.
- Test the sensor against the machine-specific diagnostic procedure before replacement.
Reset or keep running?
Do not use repeated resets as a substitute for diagnosis. If the condition involves electrical power, a motor overload, high pressure, loss of cooling, abnormal temperature, or a safety circuit, correct the underlying problem before returning the compressor to service.
Source confidence
OEM VERIFIED
This message and its troubleshooting direction are traced to the Sullair STS controller troubleshooting guide.
Source: Sullair STS Controller User Manual, part 02250241-178 R01. Referenced manual page: 31.