What does High Oil Filter dP mean on a Sullair compressor?
Short answer: Fluid (oil) filter pressure drop high. If your Sullair Touch Screen (STS) is showing High Oil Filter 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?
Pressure drop across the compressor fluid filter is high while running, usually because the filter is clogged. Low ambient temperature (thick fluid) or a sensor failure can also trigger it.
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?
- Fluid filter clogged — the most common cause
- Cold ambient (below 40°F) thickening the fluid
- Sensor failure if the warning persists with a fresh filter
Can you fix it yourself?
Yes, if your team does fluid service on this unit — change the filter and reset the reminder; warm the room if cold thickened the fluid.
Step by step — what to try, in order:
- Schedule a fluid filter change — a clogged filter is the most common cause
- If ambient temperature is below 40°F (4°C), warm the room or ask about a sump heater
- Reset the reminder on the Recommended Service screen after the filter is changed
When do you need a technician — and why?
Crews not trained on this machine, or a warning that survives a new filter, need a technician — the leftover suspects are the sensor and its tubing.
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 Oil Filter dP mean on a Sullair Touch Screen (STS)?
Fluid (oil) filter pressure drop high. Pressure drop across the compressor fluid filter is high while running, usually because the filter is clogged. Low ambient temperature (thick fluid) or a sensor failure can also trigger it.
Can I fix High Oil Filter dP on a Sullair Touch Screen (STS) myself?
Yes, if your team does fluid service on this unit — change the filter and reset the reminder; warm the room if cold thickened the fluid.
When does High Oil Filter dP on a Sullair Touch Screen (STS) need a technician?
Crews not trained on this machine, or a warning that survives a new filter, need a technician — the leftover suspects are the sensor and its tubing. Call a technician to change the fluid filter if you are not trained on this unit, or if the warning persists with a fresh filter (possible sensor or tubing issue).
Verified against service documentation: Sullair Touch Screen (STS) documentation for High Oil Filter dP (sullair.com)