High Temperature 1/2/3 — Discharge Over-Temperature Fault
The SULLAIR-HIGH-TEMPERATURE (Sullair WS Controller) diesel fault code means: High Temperature 1/2/3 — Discharge Over-Temperature Fault. This is a critical severity code.
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Common Symptoms
- WS display shows High Temperature 1, 2 or 3 and the machine faults (red LED)
- Compressor shuts down and stays inoperative until cleared
Probable Causes (Ranked by Likelihood)
- Compressor fluid level low High
- Cooler fins or tubes dirty / plugged High
- Thermal valve fault Moderate
- Low water flow or high water temperature (water-cooled units) Moderate
- Ambient temperature above 105°F (41°C) Moderate
- Temperature probe or sensor failure Low
Frequently Asked Questions
What are the actual temperature limits?
Per the manual's parameter table, air-end discharge temperature (T1) warns at 225°F and faults at 235°F time-delayed or 255°F immediate. A fault lights the red LED and keeps the compressor inoperative until the condition is fixed and STOP is pressed.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
The WS Controller is fitted to Sullair STATIONARY electric shop compressors. Portable towable Sullair units (185-class and similar) use different engine-driven controls and a different fault system — this page does not apply to them.
Replenish compressor fluid to the proper level — the factory list starts there.
Clean the cooler fins and fan blades; on water-cooled machines check for a closed valve, stopped pump or broken pipe, and increase water flow or lower water temperature as needed.
Check thermal valve operation.
If ambient exceeds 105°F (41°C), improve local ventilation.
If the machine is genuinely cool and the fault repeats, check the temperature sensor and its wiring.
Factory limits for this condition: T1 warning 225°F; fault 235°F (time-delayed) / 255°F (immediate)
Per the factory manual: after resolving a fault condition, press the STOP pad to clear the FAULTED state. If the problem persists after the recommended checks, consult your Sullair distributor or factory service.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- Sullair WS Controller User Interface Manual, P/N 02250165-411 (Table 5-1 Troubleshooting Guide)distributor-hosted copy of the official Sullair manualdistributor-hosted copy of an official Sullair factory manual
Commonly Affected Vehicles
- Sullair STATIONARY electric rotary-screw compressors with the WS Controller (including VSD packages)
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