Kolpak Walk-In Cooler Alarm LOW SUPERHEAT: Below Lower Limit
LOW SUPERHEAT on a Kolpak walk-in's ArcticFox controller means superheat is below its lower limit. Press ENTER to silence the alarm for 1 hour. Have the refrigeration system checked, since too little superheat can let liquid refrigerant reach the compressor.
High: low superheat can send liquid to the compressor, so it should be checked promptly.
- Code
- LOW SUPERHEAT
- Maker
- Kolpak
- Equipment
- Walk-in coolers & freezers
- Applies to
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
What does Kolpak LOW SUPERHEAT mean?
Superheat measures how far above its boiling point the refrigerant is when it leaves the evaporator. Too much means the coil is short of refrigerant. Too little means the coil is flooded and liquid may be heading back toward the compressor. The ArcticFox controller works superheat out from the suction pressure and the suction temperature, and when the value is below the lower limit it raises the text alarm LOW SUPERHEAT in the Alarms menu. The manual defines it only as superheat below the lower limit. The action it gives is to press ENTER to silence the alarm for 1 hour while the condition is addressed, and the alarm comes back if the system is not corrected. No causes are listed in the manual. A technician will first check that the two sensors behind the calculation are reading correctly, because a wrong reading can create the alarm without a real flooding problem.
Affected models and control systems
The manual covers the ArcticFox OEM Controller with Deluxe Display used on Kolpak walk-in coolers and freezers.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- LOW SUPERHEAT in the Alarms menu
- Alarm sounding again after an hour
- Frost on the suction line returning to the compressor
- Compressor sounding rough or running cold
Possible causes
Likely causes — what usually sits behind LOW SUPERHEAT on this control. A technician confirms which one it is before any part is replaced.
- Superheat below the lower limit
- Expansion device feeding too much refrigerant to the evaporator
- Evaporator airflow low because of a fan problem or heavy frost, so the coil cannot absorb the heat
- Suction temperature or pressure sensor reading wrongly
Safe checks before calling for service
- Press ENTER on the display to silence the alarm for 1 hour.
- Check the room temperature and make sure the evaporator fans are running.
- Look at the Alarms menu for any sensor alarms shown with it.
- Do not touch the refrigerant lines.
- Call for service and note the alarm text, the room temperature and any frost on the suction line.
How a technician diagnoses LOW SUPERHEAT
- Read the live superheat, suction pressure and suction temperature on the controller.
- Check the sensors against gauges and a line thermometer.
- Check evaporator airflow, fans and frost.
- Check the expansion device and its settings.
- Correct the cause and watch superheat settle above the lower limit.
- Confirm the compressor returns without liquid and the room reaches its set temperature.
- Liquid returning to the compressor can damage it, so measurements need to be taken with gauges by a licensed technician.
- Adjusting the expansion device is service-level work on the refrigeration circuit.
- Fan and frost checks mean working around the evaporator and live wiring.
How LOW SUPERHEAT differs from similar codes
LOW SUPERHEAT is the flooded-coil side. HIGH SUPERHEAT is its opposite, with the value above the upper limit.
Technical reference
- Document
- ArcticFox Deluxe Display - Original Instructions, Installation, Operation and Maintenance Manual
- Edition
- Part No. 500002385-4, 5/23
- Models / control
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
- Section
- ArcticFox OEM Controller - Alarms Menu, p.16
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Kolpak walk-in cooler & freezer error codes
How is this different from HIGH SUPERHEAT?
LOW SUPERHEAT means the value is below the lower limit, and HIGH SUPERHEAT means it is above the upper limit.
Is it dangerous for the compressor?
Too little superheat can let liquid reach the compressor, which is why the system should be checked soon.
Does ENTER clear it?
No. It silences the alarm for 1 hour.
Need help with Kolpak LOW SUPERHEAT?
A technician confirms the cause on site and gives you the price in writing before any work starts.