Sporlan EXV Fault Codes - Quick Reference
Sporlan (Parker Hannifin brand) makes the SEI superheat controller, ASCE control boards, and electronic expansion valves (SERI, SEI, and CDS series). Faults appear via LED indicators on the SEI controller.
| LED / Fault | Meaning | Quick Fix |
|---|---|---|
| F1 - Pressure Sensor | Pressure sensor out of range | Check transducer wiring and signal |
| F2 - Temp Sensor | Temperature sensor fault | Check NTC thermistor |
| F3 - High Superheat | Superheat above alarm setpoint | Check refrigerant charge and EXV |
| F4 - Low Superheat | Superheat below alarm setpoint | Check EXV, flood-back risk |
| F5 - Valve Fault | EXV stepper motor fault | Check valve coil wiring |
| F6 - Power Supply | Supply voltage out of range | Check 24VAC supply |
| Green LED - Normal | Operation normal | No action needed |
| Amber LED - Warning | Alarm condition | Check fault code |
| Red LED - Fault | Critical fault | Read fault code immediately |
| F7 - Communication | RS-485 fault | Check wiring and address |
Most Common Faults
F3 - High Superheat
Sporlan SEI high superheat alarm means the refrigerant leaving the evaporator is too superheated. Causes: undercharged system, restricted liquid line filter-drier, stuck EXV in closed position, or incorrect superheat setpoint. Check the SEI setpoint (typically 8–12°F for refrigeration), then check the system charge using a superheat/subcooling approach.
F4 - Low Superheat
Low superheat is the dangerous condition - liquid refrigerant reaching the compressor. Check for a failed EXV stuck open, excessive refrigerant charge, or a flooded evaporator from a defrost that didn’t complete. A suction line wet with frost all the way to the compressor is a clear low-superheat indicator.
F1 - Pressure Sensor
Sporlan uses 0–100 psig or 0–500 psig ratiometric transducers (0.5–4.5V output). Verify supply voltage (5VDC) at the transducer and measure the output signal - at 0 pressure, expect approximately 0.5V; at full scale, expect approximately 4.5V. A reading of 0V or 5V indicates a failed transducer or broken wire.
F2 - Temperature Sensor
Sporlan temp sensors are NTC thermistors, typically 10K at 25°C. Test at the board terminal. Clamp the sensor securely to the suction line with proper insulation over it - poor thermal contact causes inaccurate superheat readings and erratic valve hunting.
Parts Often Needed
| Part | Notes |
|---|---|
| SEI controller board | Replace on electronics fault |
| Sporlan EXV stepper coil | Replace on F5 valve fault |
| Pressure transducer | Replace on F1 fault |
| NTC thermistor | Replace on F2 fault |
| Liquid line filter-drier | Replace on high superheat from restriction |
Need Replacement Parts?
Finding the right replacement parts for your equipment is critical to getting it running again. Check current prices on Amazon — prices and availability change frequently.
When to Call a Pro
Sporlan EXV superheat tuning in commercial refrigeration systems requires refrigerant certification and system knowledge. Low superheat conditions can destroy compressors within minutes.