Sullivan-Palatek Compressor Fault Codes — Quick Reference
Sullivan-Palatek compressors use electronic controllers that display fault codes and shutdown alarms related to temperature, pressure, motor overload, and sensor conditions. Models include rotary screw and reciprocating units used across industrial plants and contractors.
| Fault | Meaning | Quick Fix |
|---|---|---|
| High Discharge Temp | Discharge air temperature exceeded limit | Check oil level, cooler, and fan |
| Motor Overload | Motor current exceeded setpoint | Check voltage and load demand |
| High Oil Temp | Oil temperature too high | Clean oil cooler, check oil level |
| Low Oil Pressure | Oil system fault | Check oil level and filter |
| Sensor Fault | Temp or pressure sensor signal lost | Inspect sensor and wiring |
| Emergency Stop | E-stop button activated | Reset E-stop, check for hazard |
| High Air Pressure | System pressure exceeded safety limit | Check pressure switch and unloader |
| Service Due | Maintenance interval elapsed | Perform PM and reset counter |
Most Common Faults
High Discharge Temperature
Discharge temperature shutdown is the most common fault on Sullivan-Palatek rotary screw compressors. Check the oil level first. Dirty or clogged oil coolers, failed cooling fans, and high ambient temperature all contribute. Clean cooler cores with dry air applied against normal airflow direction.
Motor Overload
Verify incoming voltage on all three phases. Voltage imbalance above 2% causes significant current imbalance. Check demand — if the compressor runs fully loaded continuously, confirm the motor is correctly sized for the application.
Low Oil Pressure
Check oil level and the oil filter condition. A clogged filter on a cold start will trip low oil pressure before the oil warms and flows freely. Replace the filter if it’s past its interval.
Parts Often Needed
| Part | Notes |
|---|---|
| Oil filter | Amazon | Replace at every service interval |
| Oil separator element | Amazon | Replace when differential pressure is high |
| Discharge temperature sensor | Search on Amazon | Inspect on repeated high-temp faults |
| Cooling fan motor | Search on Amazon | Check on high-temp shutdowns |
Jump to Fix
- High temp fault → Check oil level → Clean cooler → Verify fan operation
- Motor overload → Check voltage balance → Reduce demand → Check motor amps
- Low oil pressure → Check oil level → Replace filter → Inspect oil pump
When to Call a Pro
Repeated temperature or pressure faults after routine service indicate airend wear or cooling system failure that requires a qualified compressor technician.
How to troubleshoot Sullivan Palatek Compressor
Sullivan-Palatek compressors are oil-flooded rotary screw and reciprocating units. Rather than a long list of numbered error codes, the Sullivan-Palatek Electronic Controller (SPEC) protects the machine by displaying plain-language warning and shutdown conditions: high compressor discharge temperature, low oil pressure, motor overload, low fuel or low battery (on portable diesel units), and sensor or wiring faults. On Tier 4 portable diesel machines the display also relays engine ECU diagnostics from the engine maker (Kohler, Kubota, Deutz, Cummins, Isuzu, John Deere), so a “check engine” or derate condition is often an engine SPN/FMI code, not a compressor fault. Confirm which system tripped before you start swapping parts.
Work from cheap and likely to expensive and rare. First, check the basics that cause most shutdowns: oil level, oil filter condition, air/oil separator restriction, and a clean cooling stack. High compressor discharge temperature is the single most common shutdown driver on oil-flooded screws, and it is usually a cooling problem: low oil, a dirty or plugged oil cooler, a failed or slow cooling fan, a stuck thermostatic (mixing) valve, or high ambient heat. Clean cooler cores with dry compressed air blown against the normal airflow direction, and verify the fan actually spins up under load.
Do not assume a temperature or pressure reading is real until you have ruled out the sensor. A loose connector, corroded terminal, or failing thermistor or pressure transducer can mimic a genuine overheat or oil-pressure drop and trip a false shutdown. Inspect the sensor connector and harness first, then compare the controller reading against an independent gauge or infrared thermometer. For low-oil-pressure trips on a cold start, a clogged oil filter can restrict flow until the oil warms, so replace the filter if it is past its interval before condemning the pump.
Safety and escalation: always depressurize the receiver and separator tank and lock out power before opening any panel, since stored air and hot oil are the real hazards. Routine service (filters, oil, separator element, cooler cleaning, sensor checks) is well within reach for a maintenance tech. Call a qualified compressor technician when temperature or pressure faults return after a full service, when you suspect airend wear or a failing thermostatic valve, or when a Tier 4 engine throws an emissions or DEF-related derate that needs a dealer scan tool.
Frequently asked questions
Why does my Sullivan-Palatek keep shutting down on high discharge temperature?
High compressor discharge temperature is the most common shutdown on these oil-flooded screws, and it is almost always a cooling issue. Check the oil level first, then clean the oil cooler cores, confirm the cooling fan spins up under load, and rule out a stuck thermostatic valve or high ambient heat. If it still trips after cleaning and a fresh oil and separator service, suspect a failing sensor or airend wear.
Does a sensor fault mean the compressor is really overheating or losing oil pressure?
Not necessarily. On electronically monitored Sullivan-Palatek units, a loose connector, corroded terminal, or failing thermistor or pressure transducer can mimic a real overheat or pressure drop and cause a false shutdown. Before replacing major parts, inspect the sensor connector and wiring and compare the controller reading against an independent gauge or infrared thermometer.
What triggers a low oil pressure shutdown on a cold start?
A clogged oil filter is a frequent cause. On a cold morning the oil is thick and a filter that is past its interval restricts flow enough to trip the low-oil-pressure protection before the oil warms and flows freely. Replace the filter and verify oil level before condemning the oil pump.
When should I replace the air/oil separator element?
Replace it when the separator differential pressure climbs above the recommended limit, when you see excessive oil carryover in the service air, or at the manufacturer’s scheduled interval, whichever comes first. A plugged separator raises operating pressure and temperature and can contribute to high-temp faults.
Can I troubleshoot a Sullivan-Palatek portable diesel unit myself, or do I need a dealer?
Filters, oil, separator element, cooler cleaning, and sensor and wiring checks are all owner-serviceable. But a Tier 4 engine derate, an emissions or DEF fault, or an engine ECU code usually needs an authorized engine dealer with a scan tool, and repeated compressor faults that survive a full service point to airend or thermostatic valve work best left to a qualified compressor technician.