What it means
A monitored compressor temperature is approaching or has exceeded its configured high-temperature limit.
The STS uses high-temperature warnings before limits and lists High Temperature 1/2/3 as troubleshooting faults. A red fault means the compressor stays inoperative until the condition is corrected.
Likely causes
- High ambient temperature or poor ventilation
- Low compressor fluid level
- Thermal valve problem
- Dirty cooler fins or fan blades
- Low cooling-water flow or high cooling-water temperature on water-cooled packages
- Plugged cooler
- Temperature probe or sensor failure
Operator-safe first checks
- Check for an obvious ventilation problem or unusually high room temperature.
- Inspect external cooler-airflow paths for visible obstruction without removing guards.
- Record which temperature channel (1, 2 or 3) is named and the temperature shown before shutdown.
Trained maintenance / service checks
- Verify fluid level using the machine-specific safe procedure.
- Inspect thermal-valve operation and cooler condition.
- For water-cooled machines, verify cooling-water flow and temperature.
- Check the temperature probe, sensor wiring and actual temperature against an independent measurement.
Can the compressor keep running?
Do not repeatedly reset a high-temperature trip. Find and correct the cooling, fluid or sensing problem first.
Source confidence
OEM VERIFIED
Sullair lists ambient heat, low fluid, thermal valve, cooler, cooling-water and temperature-sensor causes for High Temperature 1/2/3.
Source: Sullair STS Controller User Manual, part 02250241-178 R01. Referenced manual page(s): 20, 32.