Sullair Compressor Fault Codes (Supervisor, STS)

Q: Where can I find a Sullair fault codes list?

Sullair prints the messages in the controller user manual, not in one combined list. The Supervisor Controller manual (02250146-049) has the troubleshooting guide and the VSD drive fault numbers, and the STS and STS 2.0 manuals (02250241-178 and 1002-6712) have Table 6-1 with every warning and fault message. This page gathers those messages with causes and first checks.

Q: Is there a Sullair compressor fault codes PDF?

Yes. Sullair hosts the controller user manuals as PDFs on sullair.com under each product support page, for example the Supervisor Controller manual on the TS-20 page and the STS manual on the LS90, LS110 and LS160 pages. The links are in the source list below.

Q: What does Drive Fault mean on a Sullair Supervisor?

On a Supervisor with a variable speed drive, Drive Fault followed by a number is a fault reported by the drive itself. Sullair uses these numbers for the least likely faults. For example Drive Fault 1 is overcurrent, 2 overvoltage, 9 undervoltage, 14 drive over temperature and 53 communication bus fault. Look up the number in the drive fault rows on this page.

Q: How do I reset a fault on a Sullair compressor?

Fix the cause first. On the Supervisor, press Stop to clear faults and warnings when the machine is stopped, or Run to clear warnings while it runs. On the STS, the Stop button clears fault messages once the compressor is stopped and the Start button resets maintenance and warning messages while it runs. Release an E-stop button before resetting, and reset motor overloads after the heater element cools.

Q: What is the difference between a warning and a fault on a Sullair STS controller?

A warning lights the amber indicator and the compressor keeps running, but the cause must be fixed soon to prevent a fault or damage. A fault lights the red indicator steady and the compressor stays stopped until the condition is corrected. The 16 most recent warning, fault and alarm messages are kept in Event History under the Maintenance menu.

Q: What causes a High Temperature fault on a Sullair compressor?

Sullair lists high ambient temperature, low fluid level, a faulty thermal valve, dirty cooler fins, and on water cooled units low water flow, warm water or a plugged cooler. A failed temperature probe can also cause it. Improve ventilation, top up the fluid, check the thermal valve, clean the coolers and check the sensor and wiring.

How faults show

Sullair controllers show text messages, not numbers, except Drive Fault numbers from a variable speed drive. Supervisor: line 1 shows the machine state (for example E-Stop) and line 2 shows the fault or warning; several alarms rotate every 2 seconds and pressing ? gives the causes of the active alarm.

Stop clears faults and warnings when the machine is stopped, Run clears warnings while running. The Fault Log keeps the last 16 faults and the Sensor Log the readings leading up to a fault. On VSD packages the Supervisor shows drive problems as Drive Fault plus a number.

STS and STS 2.0: a Fault or Warning icon appears on the home screen; the amber indicator means maintenance or a warning and the compressor keeps running, the red indicator means a fault and the compressor stays stopped until the condition is corrected.

Stop clears fault messages once stopped, Start resets maintenance and warning messages while running, and Event History keeps the 16 most recent warning, fault and alarm messages. After a power interruption, a compressor that was faulted comes back in the faulted state.

Safety first.

Sullair: only trained people who have read the manual should operate or service the compressor. Disconnect, lock out and tag all power at the source before repairs or adjustments, never leave the compressor with open electrical enclosures, and test field equipment for electrostatic fields before servicing.

On variable speed drive packages, disconnect all power and wait at least 5 minutes after all keypad lights are off before opening the drive covers, then confirm with a DC voltmeter that the DC bus capacitors are discharged. To replace the STS backup battery, stop the compressor and lock out power first.

Sources: Supervisor manual sections 1 and 6.1 (PDF pages 5, 6 and 36), STS manual 6.4 (PDF page 35). Follow lockout/tagout and your site's safe-work procedures, and check the manual for your exact model before you act.

Quick lookup

Faults stop the compressor and every line that runs on its air, so in OEE they are availability losses; warnings are early signs.

Type a message, a drive fault number or a word (temperature, pressure, sensor, dryer) to filter the list. Click a row for its causes and first checks. Each row's details name the controllers whose manual prints it.

Find a code or a word

100 codes

Message or code	What it means
Air Filter Maint	The pressure difference across the air inlet filter is high, so the filter is getting blocked.
Aux Motor Overload	An auxiliary motor overload has tripped: the cooling fan, fluid (oil) pump or another auxiliary motor.
E-Stop Push Button	The emergency stop button is pressed in, or the button or its wiring is faulty.
E-Stop String	The emergency stop string is open: the E-Stop push button circuit or, where fitted, the auxiliary E-Stop devices the customer wired into the same string.
Low Water Pressure	On water cooled machines the cooling water pressure is below 10 psi (0.7 bar).
Oil Change Due / Oil Filter Change / Separator Change Due / Air Filter Change / Oil Analysis Due / Maintenance Due	A preventive maintenance timer has run out.
Main Motor Overload	The main motor overload relay has tripped.
I/O Mod Com Error / Com Mod Com Error / Motor Mod Com Error	The network that links the display module, I/O module and optional modules is not working.
Oil Filter Maint / dP2 Oil Filter High	The pressure across the oil filter is above 20 psi (1.4 bar) while running.
P3 Oil Pressure Low / dP3 Oil Pressure Low	The oil (fluid) pressure is too low.
P1 / P2 / P3 / P4 Sensor Fail, T1 / T2 / T3 / T4 / T5 Sensor Fail	A pressure (P) or temperature (T) sensor reads out of range, so the Supervisor treats the sensor or its wiring as failed.
dP1 Separator High	The pressure across the separator element is high.
Factory Setup Error	The factory setup information in the controller needs to be checked for correct values.
P1 Sump Pressure High	The sump pressure is too high because a valve in the control system has failed.
P1 Sump Pressure Low	The sump pressure is too low while running.
T1 Discharge High / T2 Dry Side High / T3 Oil Temp High / T4 Interstage High / T5 Discharge High	A temperature probe is above its limit.
Power Interruption (Supervisor)	The Supervisor detected a power interruption: a motor starter not working, no contact at input D8, or intermittent control power.
VSD Emergency Stop (VSD code 51)	The variable speed drive reports an emergency stop: the E-stop is pressed or the E-stop wiring to the drive is broken.
VSD Com Fault (VSD code 53)	The drive detected a communication problem on the link to the Supervisor.
VSD Param Lim Fault	Wrong model, horsepower or voltage is selected in the Factory and VSD setup menus, or a communication error happened at power up or setup.
VSD Com Error	The Supervisor lost communication with the variable speed drive.
Drive Fault xx	The variable speed drive reported a fault and the Supervisor shows Drive Fault followed by the drive fault number.
Drive Fault 1	The drive measured a very high output current, more than 4 times rated current.
Drive Fault 2	The DC link voltage went above its high limit.
Drive Fault 3	The motor phase currents do not add up to zero, so current is leaking to ground.
Drive Fault 5	A start was commanded while the drive's charging switch was still open, so the drive refused to start.
Drive Fault 6	An emergency stop signal arrived on one of the drive digital inputs.
Drive Fault 7	The drive tripped on saturation, which points to a defective component or a short in the motor or its cable.
Drive Fault 8	The drive reported a general system fault.
Drive Fault 9	The DC link voltage dropped below the minimum safe operating level.
Drive Fault 10	An input line phase is low or missing.
Drive Fault 11	The drive sees no current in one motor phase.
Drive Fault 13	The drive heatsink is below 14 F (-10 C).
Drive Fault 14	The drive heatsink is above 194 F (90 C).
Drive Fault 15	The drive detected a motor stall.
Drive Fault 16	The drive motor temperature model says the motor is overheating.
Drive Fault 22	Saving parameters in the drive failed.
Drive Fault 24	The values shown on the drive counters are wrong.
Drive Fault 25	The drive processor watchdog tripped.
Drive Fault 26	The drive was stopped from starting.
Drive Fault 31 / 41	The IGBT inverter bridge overtemperature protection detected a high short term overload current (31 is the hardware detection).
Drive Fault 32	The drive cooling fan did not start when commanded.
Drive Fault 36	The control unit cannot control the power unit, or the other way round.
Drive Fault 37 / 44	An option board or the drive power unit was changed (37 same type, 44 different type).
Drive Fault 38 / 45	An option board or drive power unit was added (38 same type, 45 different type).
Drive Fault 39	An option board or drive was removed.
Drive Fault 40	The drive found an option board or drive it does not know.
Drive Fault 50	The current at the drive analog input is below 4 mA.
Drive Fault 51	A drive digital input set as an external fault input was triggered.
Drive Fault 53	The data link between the communication bus master (Supervisor) and the drive communication board failed.
Drive Fault 54	An option board or its slot in the drive is defective.
Change Air Filter / Change Fluid / Change Fluid Filter / Change Separator / Analyze Fluid / Maintenance A	A recommended service interval has expired and maintenance is due.
CE Voltage too high	The controller supply voltage from the power supply or transformer is too high.
CE Voltage too low	The controller supply voltage is too low.
Controller Watchdog	The controller detected an internal fault.
Dryer Fault / Dryer Relay Fault / Dryer Overload	The integrated dryer reports a general malfunction or a dryer overload.
High Dryer Dew point / Dryer High DP Fault / Low Dryer Dew point / Dryer Low DP Fault	The dryer cannot cool below the high dew point setting, or it is cooling below the low dew point setting.
Dryer Service	A dryer malfunction is about to happen.
Ethernet disabled	The controller disabled its Ethernet connection because of a problem, typically too much traffic.
Failed to Unload	The compressor did not unload when commanded.
High Air Filter dP	The pressure difference across the inlet air filter is high, so the element needs checking or changing.
HIGH AN_ SENSOR / LOW AN_ SENSOR	An analog sensor (pressure transducer, temperature probe and so on) reads above or below its valid range, which points to a sensor or wiring failure.
High Moisture	Too much moisture is building up, usually because a drain or absorber circuit is not working.
High Oil Filter dP / High Fluid Filter dP	The pressure difference across the fluid (oil) filter is high while running.
High Interstage Pres	Pressure between the two compression stages is too high.
High Package Press / High Pressure A / High Pressure B	The package pressure is too high.
High Separator dP	The pressure difference across the separator is high, so the separator needs checking or changing.
High Spiral Valve Pr	The pressure to the spiral valve actuator is wrong because of mis-adjustment.
High Sump Pressure	The sump pressure is too high because a control valve has failed.
High Temperature 1 / High Temperature 2 / High Temperature 3	A temperature probe is at its high limit.
High Voltage Failed	There is no power to the high voltage (medium voltage) starter.
Illegal State	The controller reached a state it should never be in: an internal controller fault.
Ethernet Comm Error	The display module lost its network link to the I/O module or another module.
Low Line Pressure	Line pressure is low because demand is more than the supply.
Low Fluid Pressure	The fluid (oil) pressure is too low.
Low Sump Pressure	The sump pressure is too low.
Low Temperature 1 / Low Temperature 2 / Low Temperature 3	A temperature probe reads near or below its low limit because the ambient air is cold.
Memory Error	The controller I/O board has failed.
Not Commissioned	The controller has been replaced and not yet set up for this compressor.
Option Input / Option Input Run / User Option Warning	A switch supplied by the user and wired to the option input has operated.
Port C Comm Error / Port E Comm Error	The wiring between the controller and the user interface panel has a fault.
Pump Motor Overload	The fluid pump motor overload has tripped.
Pump Starter Contact	The fluid pump starter did not operate, or its auxiliary contact did not confirm it.
Replace Battery	The controller I/O backup battery is low.
Sequence Comm Error	Communication failed between compressor controllers set up to run in sequence.
Spiral Valve Comm	Electronic spiral valve operation is blocked because the STS lost communication with the spiral motor driver module.
Spiral Valve Operation	Electronic spiral valve operation is blocked by an abnormal operating condition such as component temperatures.
Spiral Valve System	Electronic spiral valve operation is blocked by a system setup issue.
Starter	The main starter did not operate as commanded, or a momentary line power loss or brownout happened.
UI Voltage too high / UI Voltage too low / HIGH VOLT SENSOR / LOW VOLT SENSOR	The controller detected an internal voltage problem.
VSD1 Comm Fault	The STS lost communication with the variable speed drive.
VFD Overtemp	The variable frequency drive is running near its design temperature limit.
Power Interruption (STS)	An interruption in power to the compressor has occurred.
Ambient temp high	The air around the compressor is too hot.
Drain Valve Warning	A condensate drain has failed.
Phase Monitor	The phase protection relay has tripped.
RTD Circuit Fault	A resistance temperature sensor (RTD) circuit has failed.
High Motor Temps (Bearing, Winding)	The motor bearing or winding temperature is high.
VFD1 parameter error	The controller was initialized incorrectly for the drive.
VFD1 Response	The variable frequency drive is not responding to STS control.

Each code: causes and first checks

Air Filter Maint: Air filter maintenance

Warning: act before it becomes a stop

What it means: The pressure difference across the air inlet filter is high, so the filter is getting blocked.^[1]

Also on: Controllers: Supervisor Controller. STS controllers show High Air Filter dP (separate row).

Controller response: Warning: line 2 of the Supervisor display shows the message while the compressor runs; press Run to clear it while running (or Stop when stopped); it returns if the cause is still there

Likely causes

Dirty inlet air filter
Faulty inlet filter pressure switch

First checks, in this order

Replace the air filter element.
Check the inlet filter pressure switch.

Aux Motor Overload: Auxiliary motor overload

Hits OEE: Availability

What it means: An auxiliary motor overload has tripped: the cooling fan, fluid (oil) pump or another auxiliary motor.^[1]^[2]^[3]

Also on: Controllers: Supervisor Controller; Sullair Touch Screen (STS) Controller; STS Controller 2.0. Same text and causes on Supervisor, STS and STS 2.0.

Controller response: Fault: line 2 of the Supervisor display shows the message and the compressor stops; press ? for causes, fix the cause, then press Stop to clear the fault; logged in the Fault Log (last 16 faults) with a Sensor Log of readings before the fault

Likely causes

Overload tripped on the cooling fan, fluid pump or other motor
Loose connections
Worn motor starter contacts
Low line voltage

First checks, in this order

Reset the auxiliary overload after the element cools down.
Check the motor amps against the rating.
Check for loose connections and the starter contacts.
Check the line voltage; if it is low, consult the power company.

E-Stop Push Button: Emergency stop push button

Hits OEE: Availability

What it means: The emergency stop button is pressed in, or the button or its wiring is faulty. The STS logs an E-stop as a fault.^[1]^[2]^[3]

Also on: Controllers: Supervisor Controller; Sullair Touch Screen (STS) Controller; STS Controller 2.0. The Supervisor main display line 1 also reads E-Stop.

Likely causes

E-stop button pressed
Faulty E-stop button or wiring

First checks, in this order

Make the machine safe and release the button.
If the message stays, check the E-stop wiring.

E-Stop String: Emergency stop string open

Hits OEE: Availability

What it means: The emergency stop string is open: the E-Stop push button circuit or, where fitted, the auxiliary E-Stop devices the customer wired into the same string. The Supervisor display shows E-Stop; its Status list shows E-Stop String and Aux E-Stop as separate inputs.^[1]

Also on: Controllers: Supervisor Controller. Shown in Status as Aux E-Stop.

Likely causes

A customer auxiliary E-stop device is open
Wiring fault in the auxiliary E-stop string

First checks, in this order

Check the auxiliary E-stop devices.
Check the wiring.

Low Water Pressure: Low cooling water pressure

Hits OEE: Availability

What it means: On water cooled machines the cooling water pressure is below 10 psi (0.7 bar).^[1]^[2]^[3]

Also on: Controllers: Supervisor Controller (water cooled); Sullair Touch Screen (STS) Controller; STS Controller 2.0. Same message on Supervisor and STS controllers.

Likely causes

Closed water valve
Broken water pipe
Water pressure switch shorted or open (STS)

First checks, in this order

Check for closed valves or broken pipes.
Replace the switch if it is shorted or open and check its wiring for shorts, arcing or loose connections.

Oil Change Due / Oil Filter Change / Separator Change Due / Air Filter Change / Oil Analysis Due / Maintenance Due: Maintenance due

Warning: act before it becomes a stop

What it means: A preventive maintenance timer has run out.^[1]

Also on: Controllers: Supervisor Controller. STS controllers use Change Air Filter, Change Fluid, Change Fluid Filter, Change Separator and Analyze Fluid (separate row).

Likely causes

Maintenance interval reached

First checks, in this order

Select Maintenance from the menu to see which service is due and the part numbers.
Do the service and reset the timer.

Main Motor Overload

Hits OEE: Availability

What it means: The main motor overload relay has tripped.^[1]^[2]^[3]

Also on: Controllers: Supervisor Controller; Sullair Touch Screen (STS) Controller; STS Controller 2.0. Same message on Supervisor, STS and STS 2.0.

Likely causes

Main motor overload relay tripped
Compressor not configured correctly
Load pressure set above the compressor limit
Worn motor starter contacts
Low line voltage

First checks, in this order

Reset the overload after the heater element cools down.
Check that the compressor is configured correctly.
Make sure the load pressure is below the compressor limit.
Check the starter contacts and the line voltage; if it is low, consult the power company.

I/O Mod Com Error / Com Mod Com Error / Motor Mod Com Error: Module network error

Hits OEE: Availability

What it means: The network that links the display module, I/O module and optional modules is not working. The message names the module that lost contact.^[1]

Also on: Controllers: Supervisor Controller. VSD Com Error is in the same group (separate row). STS: Ethernet Comm Error.

Likely causes

Wiring fault on the module network
Failed module named in the message
Failed display module

First checks, in this order

Check the wiring.
Replace the module named in the message; if the problem stays, replace the display module.

Oil Filter Maint / dP2 Oil Filter High: Oil filter pressure drop high

Warning: act before it becomes a stop

What it means: The pressure across the oil filter is above 20 psi (1.4 bar) while running.^[1]

Also on: Controllers: Supervisor Controller. STS: High Oil Filter dP; STS 2.0: High Fluid Filter dP (separate row).

Likely causes

Clogged oil filter
Low ambient temperature (flooded machines)
Sensor failure

First checks, in this order

Replace the oil filter.
Below 40 F (4 C) ambient a sump heater may be needed.
Check the sensor, wiring and tubing.

P3 Oil Pressure Low / dP3 Oil Pressure Low: Low oil pressure

Hits OEE: Availability

What it means: The oil (fluid) pressure is too low.^[1]

Also on: Controllers: Supervisor Controller. STS: Low Fluid Pressure (separate row).

Likely causes

Oil pump failure
Clogged oil filter
Low sump oil level (flooded machines)
Low ambient temperature
Remote coolers without an oil pump

First checks, in this order

Replace the oil filter if clogged.
Top up the sump oil to the correct level.
Below 40 F (4 C) ambient a sump heater may be needed.
For an oil pump failure or remote coolers, consult the Sullair service department.

P1 / P2 / P3 / P4 Sensor Fail, T1 / T2 / T3 / T4 / T5 Sensor Fail: Sensor failure

Hits OEE: Availability

What it means: A pressure (P) or temperature (T) sensor reads out of range, so the Supervisor treats the sensor or its wiring as failed. On flooded screw machines a reading at the top limit (500) or a temperature at -40 counts as sensor failure.^[1]

Also on: Controllers: Supervisor Controller. T3 sensor failure is a warning on flooded screw machines per the analog alarm tables. STS: HIGH AN_ SENSOR / LOW AN_ SENSOR.

Likely causes

Failed sensor
Wiring failure

First checks, in this order

Check the sensor wiring.
Check the sensor and replace it if it has failed.

dP1 Separator High: Separator pressure drop high

Warning: act before it becomes a stop

What it means: The pressure across the separator element is high.^[1]

Also on: Controllers: Supervisor Controller (flooded machines). STS: High Separator dP (separate row).

Likely causes

Plugged separator elements
Pressure sensor failure

First checks, in this order

Replace the separator elements.
Check the pressure sensor wiring.

Factory Setup Error

Hits OEE: Availability

What it means: The factory setup information in the controller needs to be checked for correct values.^[1]

Also on: Controllers: Supervisor Controller.

Likely causes

Wrong or lost factory setup values

First checks, in this order

Have the factory setup values checked by a Sullair distributor.
If the problem stays, replace the Supervisor.

P1 Sump Pressure High: Sump pressure high

Hits OEE: Availability

What it means: The sump pressure is too high because a valve in the control system has failed.^[1]

Also on: Controllers: Supervisor Controller. STS: High Sump Pressure (separate row). The analog table also blocks a start while sump pressure is above 5 psi.

Likely causes

Failed poppet, Sullicon, spiral, blowdown or pneumatic valve
Solenoid valve fault
Pressure regulator out of adjustment
Minimum pressure check valve fault (not on oil free machines)

First checks, in this order

Check the valves and the Sullicon adjustment (Control Adjustment section of the compressor manual).
Check solenoid valve operation and wiring.
Check the pressure regulator adjustment and operation.
Check the minimum pressure check valve.

P1 Sump Pressure Low: Sump pressure low

Hits OEE: Availability

What it means: The sump pressure is too low while running. On flooded screw machines below 200 psi, sump pressure under 5 psi while running is an immediate fault.^[1]

Also on: Controllers: Supervisor Controller (flooded machines). STS: Low Sump Pressure (separate row).

Likely causes

Pressure sensor, wiring or tubing fault
Machine failed to start

First checks, in this order

Check the pressure sensor, wiring and tubing.
Check that the machine actually started.

T1 Discharge High / T2 Dry Side High / T3 Oil Temp High / T4 Interstage High / T5 Discharge High: High temperature

Hits OEE: Availability

What it means: A temperature probe is above its limit. The probe names depend on the machine type, for example T1 Interstage High on two stage machines or T1 Discharge High on single stage flooded machines.^[1]

Also on: Controllers: Supervisor Controller. Also listed: T2 Discharge High, T4 Intercool High. STS: High Temperature 1, 2, 3 (separate row).

Likely causes

Ambient above 105 F (41 C)
Low fluid level
Thermal valve fault
Dirty cooler fins
Water cooled: low water flow, high water temperature or plugged cooler
Sensor failure

First checks, in this order

Improve local ventilation if the ambient is above 105 F (41 C).
Top up the fluid to the correct level.
Check the thermal valve.
Clean the cooler fins and fan.
On water cooled units check for closed valves, pump off or broken pipe, and clean the cooler tubes.
Check the sensor and wiring.

Power Interruption (Supervisor): Power interruption

Hits OEE: Availability

What it means: The Supervisor detected a power interruption: a motor starter not working, no contact at input D8, or intermittent control power.^[1]

Also on: Controllers: Supervisor Controller. On STS controllers Power Interruption is a warning with a different cause list (separate row).

Likely causes

Motor starter not working
No contact to input D8
Intermittent control power

First checks, in this order

Check the starter controls and wiring.
Check the wiring to input D8.
Check the line voltage and connections.

VSD Emergency Stop (VSD code 51): VSD emergency stop

Hits OEE: Availability

What it means: The variable speed drive reports an emergency stop: the E-stop is pressed or the E-stop wiring to the drive is broken.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package. Drive code 51 External fault (separate row).

Likely causes

Emergency stop pressed
Break in the E-stop wiring to the drive

First checks, in this order

Clear the package emergency stop.
Check the E-stop wiring to the drive input.

VSD Com Fault (VSD code 53): VSD communication fault reported by the drive

Hits OEE: Availability

What it means: The drive detected a communication problem on the link to the Supervisor.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package. Drive code 53 Communication bus fault (separate row).

Likely causes

Intermittent control wiring to the drive
Communication bus fault

First checks, in this order

Check the connections to the VSD.
Check the VSD control power and look for board faults.

VSD Param Lim Fault: VSD parameter limit fault

Hits OEE: Availability

What it means: Wrong model, horsepower or voltage is selected in the Factory and VSD setup menus, or a communication error happened at power up or setup.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Likely causes

Incorrect factory or VSD setup
Communication error at power up or setup

First checks, in this order

Check the setup menus and make the correct model, HP and voltage selections.
Check the drive rating.

VSD Com Error: VSD communication lost

Hits OEE: Availability

What it means: The Supervisor lost communication with the variable speed drive.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package. STS: VSD1 Comm Fault; STS 2.0: VFD1 Comm Fault (separate row).

Likely causes

Loose or broken communication connection
Loss of VSD control power
Board fault

First checks, in this order

Check the connections to the VSD.
Check the VSD control power and look for board faults.

Drive Fault xx: Drive fault with number

Hits OEE: Availability

What it means: The variable speed drive reported a fault and the Supervisor shows Drive Fault followed by the drive fault number. Sullair uses these numbers for the least likely faults; the number rows below explain each one.^[1]^[4]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package. TS-20 user manual: VSD fault code, refer to the Supervisor manual.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Problem detected by the variable speed drive

First checks, in this order

Note the number after Drive Fault and look it up in the drive fault rows.

Drive Fault 1: Overcurrent

Hits OEE: Availability

What it means: The drive measured a very high output current, more than 4 times rated current.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Sudden heavy load increase
Short in the motor
Short in the cables to the motor
Unsuitable motor

First checks, in this order

Check the loading.
Check the motor.
Check the cables.

Drive Fault 2: Overvoltage

Hits OEE: Availability

What it means: The DC link voltage went above its high limit.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Deceleration time too short
High voltage levels or surges in the utility supply

First checks, in this order

Make the deceleration time longer or use a chopper and brake resistor.
Correct a too high supply voltage.
Add input impedance to limit surges.

Drive Fault 3: Ground Fault (Earth Fault)

Hits OEE: Availability

What it means: The motor phase currents do not add up to zero, so current is leaking to ground.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Insulation failure in the motor or motor cables

First checks, in this order

Check the motor and motor cables.
Remove faults from ungrounded systems.

Drive Fault 5: Charging Switch

Hits OEE: Availability

What it means: A start was commanded while the drive's charging switch was still open, so the drive refused to start.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Faulty operation
Component failure

First checks, in this order

Reset the fault and restart.
If it comes back, contact Sullair service.

Drive Fault 6: Emergency stop

Hits OEE: Availability

What it means: An emergency stop signal arrived on one of the drive digital inputs.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Emergency stop signal on a drive digital input

First checks, in this order

Find out why the emergency stop was given and fix it.

Drive Fault 7: Saturation trip

Hits OEE: Availability

What it means: The drive tripped on saturation, which points to a defective component or a short in the motor or its cable.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name; cannot be reset from the keypad

Likely causes

Defective component
Short in the motor or motor cable

First checks, in this order

Switch off power; this fault cannot be reset from the keypad.
If it appears together with Drive Fault 1, check the motor and motor cables.
If the motor and cables are good, do not reconnect power; contact Sullair service.

Drive Fault 8: System fault

Hits OEE: Availability

What it means: The drive reported a general system fault.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Component failure
Faulty operation

First checks, in this order

Reset the fault and restart.
Check the Active Fault menu and Fault Time Data Record on the drive.
If it comes back, contact Sullair service.

Drive Fault 9: Undervoltage

Hits OEE: Availability

What it means: The DC link voltage dropped below the minimum safe operating level.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Supply voltage too low (most likely)
Internal drive fault

First checks, in this order

After a supply loss or dip, reset the fault and restart.
Check the supply voltage; if it was in spec at the time, the drive has an internal failure: contact Sullair service.

Drive Fault 10: Input line supervision

Hits OEE: Availability

What it means: An input line phase is low or missing.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Missing or low supply phase
Loose supply cable or connection

First checks, in this order

Check the utility supply voltage, cables and connections.

Drive Fault 11: Output line supervision

Hits OEE: Availability

What it means: The drive sees no current in one motor phase.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Open motor cable or connection
Motor fault

First checks, in this order

Check the motor cables, connections and motor.

Drive Fault 13: Undertemperature

Hits OEE: Availability

What it means: The drive heatsink is below 14 F (-10 C).^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Drive installed in a too cold location

First checks, in this order

Provide extra heating or move the drive to a warmer location.

Drive Fault 14: Over-temperature

Hits OEE: Availability

What it means: The drive heatsink is above 194 F (90 C). A warning is given from 185 F (85 C).^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Not enough or blocked cooling air
Dust or dirt on the heatsink
High ambient temperature
Switching frequency too high for the ambient and load

First checks, in this order

Check the amount and free flow of cooling air.
Clean dust or dirt off the heatsink.
Check the highest ambient temperature.
Check that the switching frequency is not too high for the ambient and motor load.

Drive Fault 15: Motor stalled

Hits OEE: Availability

What it means: The drive detected a motor stall.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Motor or load mechanical failure
Load too high
Stall parameters set wrong

First checks, in this order

Check the motor, the mechanical system and the load.
Confirm the stall parameter settings.

Drive Fault 16: Motor over-temperature

Hits OEE: Availability

What it means: The drive motor temperature model says the motor is overheating.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Motor overloaded

First checks, in this order

Reduce the motor load.
If there is no overload, check the temperature model parameters.

Drive Fault 22: EEPROM checksum fault

Hits OEE: Availability

What it means: Saving parameters in the drive failed.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Faulty operation
Component failure

First checks, in this order

After reset the drive reloads default parameters: check all parameter settings.
If it comes back, contact Sullair service.

Drive Fault 24: Counter fault

Hits OEE: Availability

What it means: The values shown on the drive counters are wrong.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Drive counter values incorrect

First checks, in this order

The manual gives no separate action for this code: reset the fault and contact Sullair service if it comes back.

Drive Fault 25: Microprocessor watchdog fault

Hits OEE: Availability

What it means: The drive processor watchdog tripped.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Faulty operation
Component failure

First checks, in this order

Reset the fault and restart.
If it comes back, contact Sullair service.

Drive Fault 26: Startup prevented

Hits OEE: Availability

What it means: The drive was stopped from starting.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Start enable or interlock not satisfied

First checks, in this order

Check the Start Enable and Interlock settings.

Drive Fault 31 / 41: IGBT temperature

Hits OEE: Availability

What it means: The IGBT inverter bridge overtemperature protection detected a high short term overload current (31 is the hardware detection).^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Load too high for the drive
Motor size not matched to the drive

First checks, in this order

Check the loading.
Check the motor size.

Drive Fault 32: Fan cooling

Hits OEE: Availability

What it means: The drive cooling fan did not start when commanded.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Drive cooling fan failure

First checks, in this order

Contact Sullair service.

Drive Fault 36: Control Unit

Hits OEE: Availability

What it means: The control unit cannot control the power unit, or the other way round.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Control unit and power unit mismatch or failure

First checks, in this order

Change the control unit.

Drive Fault 37 / 44: Device change

Hits OEE: Availability

What it means: An option board or the drive power unit was changed (37 same type, 44 different type).^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name; no Fault Time Data Record is made

Likely causes

Option board changed
Drive of a different power rating fitted

First checks, in this order

Reset.
After 44, application parameters are back to default: set them again.

Drive Fault 38 / 45: Device added

Hits OEE: Availability

What it means: An option board or drive power unit was added (38 same type, 45 different type).^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name; no Fault Time Data Record is made

Likely causes

Option board added
Drive of a different power rating added

First checks, in this order

Reset.
After 45, application parameters are back to default: set them again.

Drive Fault 39: Device removed

Hits OEE: Availability

What it means: An option board or drive was removed.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name; no Fault Time Data Record is made

Likely causes

Option board removed
Drive removed

First checks, in this order

Reset.

Drive Fault 40: Device unknown

Hits OEE: Availability

What it means: The drive found an option board or drive it does not know.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Unknown option board or drive

First checks, in this order

Contact Sullair service.

Drive Fault 50: Analog input Iin < 4 mA

Hits OEE: Availability

What it means: The current at the drive analog input is below 4 mA.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Current at the drive analog input below 4 mA

First checks, in this order

Set drive parameter 2.6.1 to None, as Sullair directs.

Drive Fault 51: External fault

Hits OEE: Availability

What it means: A drive digital input set as an external fault input was triggered. On Sullair packages this is the emergency stop circuit.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Package emergency stop pressed
E-stop wiring to the drive input open

First checks, in this order

Clear the package emergency stop.
Check the E-stop wiring to the drive input.

Drive Fault 53: Communication bus fault

Hits OEE: Availability

What it means: The data link between the communication bus master (Supervisor) and the drive communication board failed.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Supervisor bus cable fault
Supervisor VSD setting not on Serial

First checks, in this order

Check the Supervisor bus cable.
Set Supervisor VSD to Serial.
If the installation is correct, contact Sullair service.

Drive Fault 54: Slot fault

Hits OEE: Availability

What it means: An option board or its slot in the drive is defective.^[1]

Also on: Controllers: Supervisor Controller with variable speed drive (VSD) package.

Controller response: The Supervisor shows Drive Fault with this number; a keypad service tool plugged into the drive shows the same code and the fault name

Likely causes

Defective option board or slot
Board not seated

First checks, in this order

Check that the board is installed and seated in its slot.
If it is, contact Sullair service.

Change Air Filter / Change Fluid / Change Fluid Filter / Change Separator / Analyze Fluid / Maintenance A: Service interval expired

Warning: act before it becomes a stop

What it means: A recommended service interval has expired and maintenance is due.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. STS 2.0 adds Clean Package Filter, Clean Coolers, Clean Oil Strainer, Grease Motor, Inlet Valve and Maintenance.

Controller response: Service reminder: the amber indicator lights and the compressor keeps running; reset the reminder on the Recommended Service screen after the work

Likely causes

Service interval reached

First checks, in this order

Do the recommended maintenance.
Reset the reminder on the Recommended Service screen.
For Analyze Fluid (Fluid Analysis on STS 2.0), take a fluid sample and send it for analysis.

CE Voltage too high: Control voltage too high

Hits OEE: Availability

What it means: The controller supply voltage from the power supply or transformer is too high.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Controller response: Fault: the red fault indicator lights steady and the compressor stays stopped until the condition is corrected; clear it with the Stop button once stopped; listed in Event History (16 most recent messages)

Likely causes

Excessive voltage from the power supply or transformer

First checks, in this order

Check the connections and adjustments of the power supply or transformer.

CE Voltage too low: Control voltage too low

Hits OEE: Availability

What it means: The controller supply voltage is too low.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Not enough voltage from the power supply or transformer
Excessive load or a short in the 24 V control devices

First checks, in this order

Check the connections and adjustments.
Check the wiring, coils and solenoid valves on the 24 V circuit.

Controller Watchdog

Hits OEE: Availability

What it means: The controller detected an internal fault.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Controller fault

First checks, in this order

Contact Sullair Factory Service.

Dryer Fault / Dryer Relay Fault / Dryer Overload: Dryer fault

Hits OEE: Availability

What it means: The integrated dryer reports a general malfunction or a dryer overload.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0 (machines with integrated dryer). Also printed as Dryer Overload Fault.

Likely causes

General dryer malfunction
Dryer overload tripped

First checks, in this order

Consult the dryer manual.
Contact Sullair Factory Service if needed.

High Dryer Dew point / Dryer High DP Fault / Low Dryer Dew point / Dryer Low DP Fault: Dryer dew point out of range

Hits OEE: Availability

What it means: The dryer cannot cool below the high dew point setting, or it is cooling below the low dew point setting.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0 (machines with integrated dryer). Also printed as Low Dryer Dewpoint.

Likely causes

Dryer cannot reach the dew point setting
Dryer cooling too much

First checks, in this order

Consult the dryer manual.
Contact Sullair Factory Service if needed.

Dryer Service

Warning: act before it becomes a stop

What it means: A dryer malfunction is about to happen.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Controller response: Warning: the amber maintenance/warning indicator lights and the compressor keeps running; resolve it soon to avoid a fault; clear it with the Start button while running; listed in Event History

Likely causes

Imminent dryer malfunction

First checks, in this order

Consult the dryer manual and/or Sullair Factory Service.

Ethernet disabled

Warning: act before it becomes a stop

What it means: The controller disabled its Ethernet connection because of a problem, typically too much traffic.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Excessive Ethernet traffic on the compressor network

First checks, in this order

Cut the traffic on the compressor network, for example by putting a router in front of it.

Failed to Unload

Hits OEE: Availability

What it means: The compressor did not unload when commanded.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Inlet valve or unloading controls not working

First checks, in this order

Check the operation of the inlet valve and controls.

High Air Filter dP: High air filter pressure drop

Warning: act before it becomes a stop

What it means: The pressure difference across the inlet air filter is high, so the element needs checking or changing.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor: Air Filter Maint.

Likely causes

Dirty inlet filter
Faulty inlet filter pressure switch

First checks, in this order

Replace the filter.
Check the inlet filter pressure switch.

HIGH AN_ SENSOR / LOW AN_ SENSOR: Analog sensor out of range

Hits OEE: Availability

What it means: An analog sensor (pressure transducer, temperature probe and so on) reads above or below its valid range, which points to a sensor or wiring failure.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor equivalent: P or T Sensor Fail.

Likely causes

Failed sensor
Wiring failure

First checks, in this order

Check the sensor wiring.
Check the sensor and replace it if it has failed.

High Moisture

Warning: act before it becomes a stop

What it means: Too much moisture is building up, usually because a drain or absorber circuit is not working.^[2]

Also on: Controllers: Sullair Touch Screen (STS) Controller.

Likely causes

Moisture drain malfunction
Drain interval set too long
Plugged moisture drain strainer
Too little oil flow to the absorber module (plugged orifice or strainer)

First checks, in this order

Check the wiring and operation of the moisture drain; replace it if needed.
Increase the drain rate or open time.
Clean the drain strainer.
Clean the strainers and orifices in the absorber oil line.

High Oil Filter dP / High Fluid Filter dP: High fluid filter pressure drop

Warning: act before it becomes a stop

What it means: The pressure difference across the fluid (oil) filter is high while running.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller (High Oil Filter dP); STS Controller 2.0 (High Fluid Filter dP). Supervisor: Oil Filter Maint / dP2 Oil Filter High.

Likely causes

Clogged fluid filter
Low ambient temperature
Sensor failure

First checks, in this order

Replace the fluid filter.
Below 40 F (4 C) ambient a sump heater may be needed.
Check the sensor, wiring and tubing.

High Interstage Pres: High interstage pressure

Hits OEE: Availability

What it means: Pressure between the two compression stages is too high.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0 (two stage machines).

Likely causes

Interstage blockage
Second stage failure

First checks, in this order

Inspect for an interstage flow restriction or a damaged air end and repair.

High Package Press / High Pressure A / High Pressure B: High package pressure

Hits OEE: Availability

What it means: The package pressure is too high.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Valves or controls not working
Faulty pressure sensor

First checks, in this order

Check the operation of the valves and controls.
Check the pressure sensor and replace it if defective.

High Separator dP: High separator pressure drop

Warning: act before it becomes a stop

What it means: The pressure difference across the separator is high, so the separator needs checking or changing.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor: dP1 Separator High.

Likely causes

Plugged separator elements
Pressure sensor failure

First checks, in this order

Inspect and replace the separator.
Check the sensor wiring.

High Spiral Valve Pr: High spiral valve pressure

Warning: act before it becomes a stop

What it means: The pressure to the spiral valve actuator is wrong because of mis-adjustment.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Spiral valve actuator regulator mis-adjusted

First checks, in this order

Check how the spiral valve actuator's pressure regulator is set.

High Sump Pressure

Hits OEE: Availability

What it means: The sump pressure is too high because a control valve has failed.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor: P1 Sump Pressure High.

Likely causes

Failed poppet, Sullicon, spiral, blowdown or pneumatic valve
Faulty solenoid valves
Faulty pressure regulator
Minimum pressure check valve fault (not on fluid free machines)

First checks, in this order

Check the valves and the Sullicon adjustment (Control Adjustment section of the compressor manual).
Check solenoid valve operation and wiring.
Check the pressure regulator adjustment and operation.
Check the minimum pressure check valve.

High Temperature 1 / High Temperature 2 / High Temperature 3: High temperature

Hits OEE: Availability

What it means: A temperature probe is at its high limit. As a warning the same message means the temperature is approaching the limit; at the limit it becomes a fault.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0 (High Temperature(s)). Supervisor: T1 Discharge High and related messages.

Likely causes

High ambient temperature
Low fluid level
Thermal valve fault
Dirty cooler fins
Water cooled: low water flow, high water temperature or plugged cooler
Dirty inlet filter on oil free first stage (STS 2.0)
Temperature probe or sensor failure

First checks, in this order

Improve local ventilation.
Top up the fluid to the correct level.
Check the thermal valve.
Clean the cooler fins and fan blades.
On water cooled units check valves, pump and pipes, increase water flow and clean the cooler.
Check the sensor and wiring.

High Voltage Failed

Hits OEE: Availability

What it means: There is no power to the high voltage (medium voltage) starter.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Disconnect switch open
Main motor fuses or circuit breaker open

First checks, in this order

Close the disconnect switch.
Check the main motor fuses or circuit breaker.

Illegal State

Hits OEE: Availability

What it means: The controller reached a state it should never be in: an internal controller fault.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Controller fault

First checks, in this order

Contact Sullair Factory Service.

Ethernet Comm Error: Module network error

Hits OEE: Availability

What it means: The display module lost its network link to the I/O module or another module.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor: I/O Mod Com Error and related.

Likely causes

Wiring fault on the module network

First checks, in this order

Check the wiring.

Low Line Pressure

Warning: act before it becomes a stop

What it means: Line pressure is low because demand is more than the supply.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Demand exceeds capacity
Leaks in supply lines

First checks, in this order

Reduce demand or add capacity.
Check for leaks or open lines in the air supply and repair them.

Low Fluid Pressure

Hits OEE: Availability

What it means: The fluid (oil) pressure is too low. STS 2.0 prints it as Low Fluid Pressure or Injection Pressure.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor: P3 Oil Pressure Low.

Likely causes

Clogged fluid filter
Low sump fluid level
Low ambient temperature
Fluid pump failure

First checks, in this order

Replace the fluid filter.
Top up the fluid to the correct level.
Below 40 F (4 C) ambient a sump heater may be needed.
A fluid pump may be required for remote coolers; consult Sullair Factory Service.

Low Sump Pressure

Hits OEE: Availability

What it means: The sump pressure is too low.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Supervisor: P1 Sump Pressure Low.

Likely causes

Bad sensor or connections
Machine failed to start

First checks, in this order

Check the pressure sensor, wiring and tubing.
Check machine operation.

Low Temperature 1 / Low Temperature 2 / Low Temperature 3: Low temperature

Warning: act before it becomes a stop

What it means: A temperature probe reads near or below its low limit because the ambient air is cold.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Low ambient air temperature

First checks, in this order

Below 40 F (4 C) ambient a sump heater may be needed.

Memory Error

Hits OEE: Availability

What it means: The controller I/O board has failed.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Failed controller I/O board

First checks, in this order

The board needs replacing: contact Sullair Factory Service.

Not Commissioned

Hits OEE: Availability

What it means: The controller has been replaced and not yet set up for this compressor.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Controller replaced and not initialized

First checks, in this order

Follow the commissioning procedure to set the controller up for the specific compressor package.

Option Input / Option Input Run / User Option Warning: Option input

Warning: act before it becomes a stop

What it means: A switch supplied by the user and wired to the option input has operated. On the STS, User Option Warning can also mean a user supplied external phase protection relay tripped.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Controller response: Warning or fault depending on how the option input is set up

Likely causes

User supplied switch operated
User supplied phase protection relay tripped

First checks, in this order

Check the operation of the optional device.
For a phase relay, follow the troubleshooting steps in the phase relay documentation supplied by the user.

Port C Comm Error / Port E Comm Error: User interface communication error

Hits OEE: Availability

What it means: The wiring between the controller and the user interface panel has a fault.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0 prints it as Internal Comm Error.

Likely causes

Cable or connection fault between controller and user interface panel

First checks, in this order

Check the cable and connections.

Pump Motor Overload

Hits OEE: Availability

What it means: The fluid pump motor overload has tripped.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Fluid pump motor overload tripped
Loose connections
Worn starter contacts
Low line voltage

First checks, in this order

Reset the overload after the element cools; check the motor amps.
Check for loose connections and the starter contacts.
Check the line voltage.

Pump Starter Contact

Hits OEE: Availability

What it means: The fluid pump starter did not operate, or its auxiliary contact did not confirm it.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Pump starter failed to operate
Faulty auxiliary contact

First checks, in this order

Check the starter and control wiring.
Check the auxiliary contact and its wiring.

Replace Battery

Warning: act before it becomes a stop

What it means: The controller I/O backup battery is low. It keeps the clock and memory records when power is off.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. Warning list name: Replace I/O Battery.

Likely causes

Low backup battery

First checks, in this order

Stop the compressor, lock out power, open the I/O control module and replace the battery with a BR2032.

Sequence Comm Error: Sequence communication error

Warning: act before it becomes a stop

What it means: Communication failed between compressor controllers set up to run in sequence.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Cable or connection fault between compressors
Wrong sequence settings

First checks, in this order

Check the wiring.
Check the sequence settings of all compressors in the sequence.

Spiral Valve Comm: Spiral valve communication

Warning: act before it becomes a stop

What it means: Electronic spiral valve operation is blocked because the STS lost communication with the spiral motor driver module.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Loose power cable at the driver module
A fault in the communication cable from the STS I/O module to the spiral motor driver
Replacement driver switches set wrong

First checks, in this order

Check the power cable connection to the driver module.
Check the communication cable that runs from the STS I/O module to the spiral motor driver.
On a replacement driver module, check the driver switch settings.

Spiral Valve Operation

Warning: act before it becomes a stop

What it means: Electronic spiral valve operation is blocked by an abnormal operating condition such as component temperatures. It tends to clear itself when conditions return to normal.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

High ambient conditions
Low temperature start up

First checks, in this order

Check for high ambient conditions and low temperature start up.

Spiral Valve System

Warning: act before it becomes a stop

What it means: Electronic spiral valve operation is blocked by a system setup issue.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Cable connection problem between the spiral motor driver and the motor

First checks, in this order

Check the cable from the spiral motor driver to the motor.

Starter

Hits OEE: Availability

What it means: The main starter did not operate as commanded, or a momentary line power loss or brownout happened.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Main starter failed to operate
Faulty auxiliary contact
Momentary line power loss or brownout

First checks, in this order

Check the starter and control wiring.
Check the auxiliary contact and its wiring.
Check the line power quality.

UI Voltage too high / UI Voltage too low / HIGH VOLT SENSOR / LOW VOLT SENSOR: Controller voltage fault

Hits OEE: Availability

What it means: The controller detected an internal voltage problem.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Controller fault

First checks, in this order

Contact Sullair Factory Service.

VSD1 Comm Fault: VSD communication fault

Hits OEE: Availability

What it means: The STS lost communication with the variable speed drive.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0 (VFD1 Comm Fault, VF Drive Fault, V53 Fieldbus). Supervisor: VSD Com Error.

Likely causes

Loose or broken communication connection
Loss of VSD control power
Board fault

First checks, in this order

Check the connections to the VSD.
Check the VSD control power and look for board faults.

VFD Overtemp: VFD over temperature

Warning: act before it becomes a stop

What it means: The variable frequency drive is running near its design temperature limit.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0.

Likely causes

Poor ventilation
Dirty drive cooling

First checks, in this order

Make sure ventilation is adequate.
Schedule a cleaning before a high temperature fault occurs.

Power Interruption (STS): Power interruption

Warning: act before it becomes a stop

What it means: An interruption in power to the compressor has occurred.^[2]^[3]

Also on: Controllers: Sullair Touch Screen (STS) Controller; STS Controller 2.0. STS 2.0 also logs Instantaneous Power Interruption, shown only as a record that the machine lost power. Supervisor Power Interruption is a separate row.

Likely causes

Intermittent control power

First checks, in this order

Check the line voltage and connections.

Ambient temp high: Ambient temperature high

Warning: act before it becomes a stop

What it means: The air around the compressor is too hot.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

High temperature around the compressor

First checks, in this order

Improve ventilation.

Drain Valve Warning

Warning: act before it becomes a stop

What it means: A condensate drain has failed.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

Failed condensate drain

First checks, in this order

Service or replace the condensate drain.

Phase Monitor

Hits OEE: Availability

What it means: The phase protection relay has tripped.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

Phases connected wrong
Phase protection relay tripped

First checks, in this order

Confirm the phase connections and the rotation of the air end and fan.

RTD Circuit Fault

Hits OEE: Availability

What it means: A resistance temperature sensor (RTD) circuit has failed.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

Damaged wiring
Failed sensor

First checks, in this order

Check the wiring; replace the sensor if it has failed.

High Motor Temps (Bearing, Winding): High motor temperatures

Hits OEE: Availability

What it means: The motor bearing or winding temperature is high.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

High ambient temperature
Dirty motor cooling fins

First checks, in this order

Improve ventilation where the machine is installed.
Clean the motor.

VFD1 parameter error: VFD parameter error

Hits OEE: Availability

What it means: The controller was initialized incorrectly for the drive.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

Controller initialized incorrectly

First checks, in this order

Initialize the controller as shown on the machine nameplate.

VFD1 Response: VFD not responding

Hits OEE: Availability

What it means: The variable frequency drive is not responding to STS control.^[3]

Also on: Controllers: STS Controller 2.0.

Likely causes

Drive not responding to the controller

First checks, in this order

Remove power for 1 minute, restore power for 1 minute, then restart the machine.

Log it, or the same alarm comes back

A compressor alarm stops the compressor, and when compressed air drops, every machine that needs it stops too, so in OEE terms it is a breakdown for each line it feeds. Log the message, the compressor and the minutes lost on the lines; warnings are early signs worth logging.

Reason code: the message plus the compressor, for example Sullair Supervisor T1 Discharge High, compressor 2, so a cooler that clogs every summer shows up as a pattern.
Loss bucket: a stop that needs a reset, a part or a technician is an availability loss (breakdown). Stops shorter than your micro-stop threshold go to performance (minor stops). The six big losses page shows where each one belongs.
What to count: how often each code fires per week and the minutes it costs. Two numbers a week turn "that alarm comes up sometimes" into a ranked list. The MTBF and MTTR calculator and the downtime cost calculator do the math.

The free OEE tracker logs each stop with its reason and turns the week into a downtime Pareto, so the code that costs the most rises to the top.

fabrico.io has an air compressor troubleshooting guide. An alarm tells you what the controller measured, not what the lines downstream lost while the air was gone. Fabrico's camera-based OEE software syncs line camera video with machine data, so you can replay the moment a line stopped next to the cause.

Frequently asked questions

Where can I find a Sullair fault codes list?

Sullair prints the messages in the controller user manual, not in one combined list. The Supervisor Controller manual (02250146-049) has the troubleshooting guide and the VSD drive fault numbers, and the STS and STS 2.0 manuals (02250241-178 and 1002-6712) have Table 6-1 with every warning and fault message. This page gathers those messages with causes and first checks.

Is there a Sullair compressor fault codes PDF?

Yes. Sullair hosts the controller user manuals as PDFs on sullair.com under each product support page, for example the Supervisor Controller manual on the TS-20 page and the STS manual on the LS90, LS110 and LS160 pages. The links are in the source list below.

What does Drive Fault mean on a Sullair Supervisor?

On a Supervisor with a variable speed drive, Drive Fault followed by a number is a fault reported by the drive itself. Sullair uses these numbers for the least likely faults. For example Drive Fault 1 is overcurrent, 2 overvoltage, 9 undervoltage, 14 drive over temperature and 53 communication bus fault. Look up the number in the drive fault rows on this page.

How do I reset a fault on a Sullair compressor?

Fix the cause first. On the Supervisor, press Stop to clear faults and warnings when the machine is stopped, or Run to clear warnings while it runs. On the STS, the Stop button clears fault messages once the compressor is stopped and the Start button resets maintenance and warning messages while it runs. Release an E-stop button before resetting, and reset motor overloads after the heater element cools.

What is the difference between a warning and a fault on a Sullair STS controller?

A warning lights the amber indicator and the compressor keeps running, but the cause must be fixed soon to prevent a fault or damage. A fault lights the red indicator steady and the compressor stays stopped until the condition is corrected. The 16 most recent warning, fault and alarm messages are kept in Event History under the Maintenance menu.

What causes a High Temperature fault on a Sullair compressor?

Sullair lists high ambient temperature, low fluid level, a faulty thermal valve, dirty cooler fins, and on water cooled units low water flow, warm water or a plugged cooler. A failed temperature probe can also cause it. Improve ventilation, top up the fluid, check the thermal valve, clean the coolers and check the sensor and wiring.

Sources

Codes and meanings follow the manufacturer documentation below. Wording is ours, simplified for the shop floor; the manual for your exact model and software version wins if it differs.

See the moment the line stopped

Fabrico, a light MES with computer vision, syncs camera footage with machine and timeline data, so you can replay the exact moment the line stopped and review the cause next to the compressor fault. Cameras also catch short stops and a line that is switched on but not producing, the losses nobody writes down. Machines connect through a PLC, a Fabrico IoT device or an AI camera.

Book a Fabrico demo

The lookup stays free.

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