Why does my Sullair compressor keep shutting down on high temperature?
Short answer: High compressor temperature trip. If your Sullair Touch Screen (STS) is showing High Temperature 1 / 2 / 3, the controller has logged a specific, documented condition. This page covers what it means, what causes it, what you can safely fix yourself, and when — and why — it takes a technician.
What exactly is the machine telling you?
The temperature at the indicated probe has exceeded the set high limit and the controller shuts the compressor down (High Temp Fault). Sullair lists high ambient above 105°F (41°C), low fluid level, a stuck thermal valve, dirty cooler fins, or a failed temperature probe as the usual causes.
Which machines show this?
current-generation Sullair stationary rotary screw compressors — the LS-series and related packages built from the late 2010s onward — fitted with the 10-inch Sullair Touch Screen (STS) controller. The STS spells out problems as plain-English named faults and warnings ('High Temperature 1', 'Failed to Unload', 'Replace I/O Battery') rather than bare code numbers, and pairs them with live readings and a Recommended Service screen that tracks filter and separator hours. Warnings keep the machine running; faults shut it down until reset. Practical tip: before clearing anything, photograph the fault screen and the Recommended Service page — the service-hour counters usually point straight at the consumable that caused the trip.
What causes it?
- Ambient above 105°F (41°C) or poor ventilation around the package
- Compressor fluid level low
- Thermal valve stuck, or cooler fins matted with dust
- On water-cooled units, water valves closed or the pump off
- Failed temperature probe (the case that persists after everything else checks out)
Can you fix it yourself?
Often, yes — Sullair's own cause list starts with ambient, fluid level, and dirty coolers, all of which plant staff can correct before resetting with Stop.
Step by step — what to try, in order:
- Check ambient temperature and improve ventilation around the package if the room is above 105°F (41°C)
- With the unit stopped and cooled, check the compressor fluid level and top up to the proper level
- Clean the cooler fins and fan blades of dust and debris
- On water-cooled units, confirm cooling water valves are open and the pump is running
- After cooldown, press Stop to reset and restart while watching the temperature
When do you need a technician — and why?
Repeat trips after cleaning and top-up point at the thermal valve or temperature probe, which need gauge-and-meter diagnosis to replace correctly.
If it does come to a service call and you're in Nashville, TN or Birmingham, AL, we maintain independently compiled lists of local companies that service industrial air compressors — real businesses with verified contact information, none of whom paid to be listed.
Related questions
What does High Temperature 1 / 2 / 3 mean on a Sullair Touch Screen (STS)?
High compressor temperature trip. The temperature at the indicated probe has exceeded the set high limit and the controller shuts the compressor down (High Temp Fault). Sullair lists high ambient above 105°F (41°C), low fluid level, a stuck thermal valve, dirty cooler fins, or a failed temperature probe as the usual causes.
Can I fix High Temperature 1 / 2 / 3 on a Sullair Touch Screen (STS) myself?
Often, yes — Sullair's own cause list starts with ambient, fluid level, and dirty coolers, all of which plant staff can correct before resetting with Stop.
When does High Temperature 1 / 2 / 3 on a Sullair Touch Screen (STS) need a technician?
Repeat trips after cleaning and top-up point at the thermal valve or temperature probe, which need gauge-and-meter diagnosis to replace correctly. Call a service technician if the trip repeats after cleaning the cooler and correcting fluid level — the thermal valve or temperature sensor may need replacement.
Verified against service documentation: Sullair Touch Screen (STS) documentation for High Temperature 1 / 2 / 3 (sullair.com)