SULLAIR-LOW-FLUID-PRESSURE serious Sullair WS Controller

Low Fluid Pressure

The SULLAIR-LOW-FLUID-PRESSURE (Sullair WS Controller) diesel fault code means: Low Fluid Pressure. This is a serious severity code.

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DIY difficulty
moderate
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Common Symptoms

  • WS display shows Low Fluid Pressure

Probable Causes (Ranked by Likelihood)

  • Fluid filter clogged High
  • Sump fluid level low High
  • Low ambient temperature Moderate
  • Fluid pump failure (remote-cooler installations) Moderate

Step-by-Step Diagnostic Procedure

  1. 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.

  2. Replace the fluid filter and replenish fluid to the proper level.

  3. In ambients below 40°F (4°C) a sump heater may be required.

  4. On installations with remote coolers, a fluid pump may be required — consult Sullair factory service.

  5. 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.

Frequently Asked Questions

Why does cold weather trigger this?

Cold fluid is thick fluid: below about 40°F (4°C) it resists flowing, which reads as low fluid pressure. The factory remedy is a sump heater rather than parts replacement.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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