Sullair LS Series Error Code S001

Sullair Compressor Critical Temperature

Model: LS Series | Code: S001

Applicable Systems
LS Series

Symptoms

Sump (oil) temperature has exceeded 110C (230F). The high sump temperature switch opens, stopping the compressor to prevent oil degradation and airend damage.

Possible Causes

  • Dirty oil cooler with blocked fins or oil passages reducing heat rejection
  • Thermostatic valve failed in the bypass position, routing hot oil around the cooler
  • Excessive ambient temperature or restricted ventilation around the compressor enclosure
  • Continuous run at 100% load beyond the thermal design duty cycle

Troubleshooting Steps

  1. Step 1: Measure actual sump temperature with an infrared gun and compare to the controller reading
    If the reading is accurate, shut down and clean the oil cooler fins with foaming cleaner
  2. Step 2: Remove the thermostatic valve and test in a hot water bath at 75C and 85C
    The valve should begin opening at 75C and be fully open at 85C. Replace if stuck
  3. Step 3: Check compressor room ventilation - verify exhaust fans are running and intake grilles are not blocked
    Add supplemental ventilation if ambient temperature consistently exceeds 40C
  4. Step 4: Review the load/unload duty cycle from the controller trend logs
    If the unit runs loaded >95% of the time, consider a larger compressor or add a receiver tank to reduce cycle frequency

How to Reset

Reset: Allow sump temperature to drop below 95C. Press the Reset button on the Sullair controller. The unit performs a 10-second pre-lube before attempting to start.

Common Replacement Parts

  • 2500-3800-00: Oil cooler, LS 16-25 (Tube-and-fin, 500x300x50 mm, Cu/Al)
  • 2500-3801-00: Thermostatic valve, 1-inch (Opens 75C, full open 85C, 45 L/min)
  • 2500-3802-00: High sump temperature switch (Bi-metallic, 110C NC, 1/2 NPT)

Frequently Asked Questions

  • Q: What is the normal sump temperature range?

    70-95C (158-203F) under load. During unloaded idle, 55-70C is typical. Sustained operation above 100C shortens oil life by half for every 10C rise.

  • Q: Can I add a larger cooler to prevent this alarm?

    Yes, an auxiliary oil cooler can be added for high-temperature environments. Consult Sullair application engineering for sizing.

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Source: Sullair LS Series Operation and Maintenance Manual, 02250141-841

Category: Compressor

Published: 2026-10-17