High Air Filter dP — Inlet Filter Restricted
The SULLAIR-HIGH-AIR-FILTER-DP (Sullair WS Controller) diesel fault code means: High Air Filter dP — Inlet Filter Restricted. This is a moderate severity code.
- DIY difficulty
- moderate
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Common Symptoms
- WS display shows High Air Filter dP
Probable Causes (Ranked by Likelihood)
- Inlet air filter restricted High
- Inlet filter pressure switch fault Low
Frequently Asked Questions
Can I keep running with this warning?
Briefly — it is a restriction warning, not a shutdown. But a starved inlet costs capacity and drives temperatures up, so treat it as due maintenance rather than something to ignore.
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.
Replace the inlet air filter.
If the message persists with a fresh filter, check the inlet filter pressure switch.
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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