Start with a visual inspection
Sullair recommends a detailed visual inspection before repair. Look for loose or damaged wiring that is visible without opening restricted enclosures, damaged piping, leaks, overheating marks and burnt odor.
Use the exact message
Do not troubleshoot from a generic symptom such as “compressor stopped.” Search the exact STS message because the controller distinguishes sensor, pressure, overload, communication and maintenance conditions.
Do not shotgun parts
The troubleshooting table is a guide to common causes, not proof that the first listed component is bad. Verify the condition systematically and use the compressor-specific operator/service manual for deeper machine work.
Source
Based on Sullair STS Controller User Manual, part 02250241-178 R01, referenced pages 29-30.