What it means
Cooling-water pressure is below the controller threshold on a water-cooled package.
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
- Cooling-water pressure below 10 psi (0.7 bar)
- Closed valve or broken/restricted pipe
- Pressure switch open/short or wiring fault
Operator-safe first checks
- Confirm the facility cooling-water supply is available.
- Look for an externally visible closed valve, leak or broken line without entering a hazardous area.
Trained maintenance / service checks
- Restore correct cooling-water flow/pressure.
- Inspect the pressure switch and wiring for shorts, open circuits, arcing or loose connections.
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: 33.