What it means
The auxiliary overload for the compressor fluid-pump motor has tripped.
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
- Fluid-pump motor overload
- Loose connection
- Starter-contact problem
- Low line voltage
Operator-safe first checks
- Do not repeatedly reset the pump motor overload if it trips again.
- Record whether the compressor was cold, hot or under load when it occurred.
Trained maintenance / service checks
- Allow the overload element to cool before reset.
- Verify pump-motor current, starter contacts, connections and line voltage.
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: 34.