Kolpak Walk-In Cooler Alarm HIGH SUPERHEAT: Above Upper Limit
HIGH SUPERHEAT on a Kolpak walk-in's ArcticFox controller means superheat is above its upper limit. Press ENTER to silence the alarm for 1 hour. Call for service, because superheat depends on the refrigeration system.
High: the evaporator may not be getting enough refrigerant, so cooling can fall behind.
- Code
- HIGH SUPERHEAT
- Maker
- Kolpak
- Equipment
- Walk-in coolers & freezers
- Applies to
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
What does Kolpak HIGH SUPERHEAT mean?
Superheat is how many degrees the refrigerant vapor leaving the evaporator is above its boiling point at the suction pressure. A little superheat shows that the coil is fully used and that liquid is not returning to the compressor. The ArcticFox controller works the number out from the suction pressure and suction temperature, and it raises the text alarm HIGH SUPERHEAT in the Alarms menu when the value is above the upper limit. The manual gives that definition and one action: press ENTER to silence the alarm for 1 hour while the condition is addressed. The alarm sounds again if it is not corrected. No causes are listed. High superheat generally means the coil is starved of refrigerant, though the manual does not state that. The sensor alarms are worth checking first, since a bad pressure or suction temperature reading would produce the same message.
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
- HIGH SUPERHEAT in the Alarms menu
- Alarm returning after an hour
- Room temperature rising or recovering slowly
- Evaporator coil only partly frosted
Possible causes
Likely causes — what usually sits behind HIGH SUPERHEAT on this control. A technician confirms which one it is before any part is replaced.
- Superheat above the upper limit
- Evaporator starved of refrigerant because of a low charge or a restriction in the liquid line
- Expansion device not feeding enough refrigerant to the coil
- A wrong sensor reading making superheat look high
Safe checks before calling for service
- Press ENTER on the display to silence the alarm for 1 hour.
- Check the room temperature with a thermometer.
- Look at the Alarms menu for sensor alarms alongside this one.
- Keep the door closed and do not add warm product.
- Call for service and give the alarm text, the room temperature and whether it is slow to pull down.
How a technician diagnoses HIGH SUPERHEAT
- Read the Alarms menu and the live superheat, suction pressure and suction temperature.
- Rule out the sensor alarms first by checking sensors against a gauge and thermometer.
- Check the refrigerant charge, sight glass and liquid line for a restriction.
- Check the expansion device's operation and settings.
- Correct the cause and watch superheat settle inside its limits.
- Confirm the room reaches its set temperature.
- Superheat is measured with refrigerant gauges and a line thermometer, which is licensed refrigeration work.
- Charge and restriction problems need refrigerant recovery and handling.
- The expansion device settings belong to the controller's service data.
How HIGH SUPERHEAT differs from similar codes
HIGH SUPERHEAT is the starved-coil side. LOW SUPERHEAT is the opposite, with superheat below the lower 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
What is superheat?
It is how far above its boiling point the refrigerant vapor is at the evaporator outlet.
Could it be a sensor problem?
Yes. A bad pressure or suction temperature sensor would make superheat read wrongly.
Will the walk-in warm up?
It may. Watch the room temperature and call for service.
Need help with Kolpak HIGH SUPERHEAT?
A technician confirms the cause on site and gives you the price in writing before any work starts.