Separator dP High — Plugged Separator
The SULLAIR-SEPARATOR-DP-HIGH (Sullair WS Controller) diesel fault code means: Separator dP High — Plugged Separator. This is a serious severity code.
- DIY difficulty
- moderate
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Common Symptoms
- WS display shows Separator dP High (fault) or High Separator dP (warning)
Probable Causes (Ranked by Likelihood)
- Plugged separator element(s) High
- Pressure sensor failure Moderate
Frequently Asked Questions
When does the warning trip?
Per the parameter table, the separator dP warning is based on P2−P1 with a 10 psid offset allowance for an aftercooler or dryer. Rising dP over time is the separator loading up — replacement is maintenance, not failure.
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 separator element — plugging is the factory's primary cause.
Check the sensor wiring before and after: a sensor fault produces the same reading.
Factory limits for this condition: warning threshold: P2-P1 + 10 psid offset
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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