What does High Separator dP mean on a Sullair compressor?
Short answer: High pressure drop across air/fluid separator. If your Sullair Touch Screen (STS) is showing High Separator dP, the controller has logged a specific, documented condition. This page covers what it means, what causes it, what you can safely fix yourself, and when — and why — it takes a technician.
What exactly is the machine telling you?
The pressure differential across the fluid separator has exceeded the set limit, indicating plugged separator elements or a pressure sensor failure. This wastes energy and can shut the machine down.
Which machines show this?
current-generation Sullair stationary rotary screw compressors — the LS-series and related packages built from the late 2010s onward — fitted with the 10-inch Sullair Touch Screen (STS) controller. The STS spells out problems as plain-English named faults and warnings ('High Temperature 1', 'Failed to Unload', 'Replace I/O Battery') rather than bare code numbers, and pairs them with live readings and a Recommended Service screen that tracks filter and separator hours. Warnings keep the machine running; faults shut it down until reset. Practical tip: before clearing anything, photograph the fault screen and the Recommended Service page — the service-hour counters usually point straight at the consumable that caused the trip.
What causes it?
- Separator elements plugged — usually simply at the end of their service life
- Pressure sensor failure giving a false differential reading
Can you fix it yourself?
The check is in-house — read the separator hours on the Recommended Service screen and confirm connectors are seated. The element change is not.
Step by step — what to try, in order:
- Note the separator service hours on the Recommended Service screen — a separator at end of life is the most common cause
- Have the separator element replaced at the next service window
- Check that sensor wiring connectors are seated (visual check only, power off)
When do you need a technician — and why?
The separator sits inside the pressurized sump, so replacement goes to a qualified technician from your Sullair distributor.
If it does come to a service call and you're in Nashville, TN or Birmingham, AL, we maintain independently compiled lists of local companies that service industrial air compressors — real businesses with verified contact information, none of whom paid to be listed.
Related questions
What does High Separator dP mean on a Sullair Touch Screen (STS)?
High pressure drop across air/fluid separator. The pressure differential across the fluid separator has exceeded the set limit, indicating plugged separator elements or a pressure sensor failure. This wastes energy and can shut the machine down.
Can I fix High Separator dP on a Sullair Touch Screen (STS) myself?
The check is in-house — read the separator hours on the Recommended Service screen and confirm connectors are seated. The element change is not.
When does High Separator dP on a Sullair Touch Screen (STS) need a technician?
The separator sits inside the pressurized sump, so replacement goes to a qualified technician from your Sullair distributor. Call your Sullair distributor to replace the separator element — it sits inside the pressurized sump and must be changed by a qualified technician.
Verified against service documentation: Sullair Touch Screen (STS) documentation for High Separator dP (sullair.com)