Polar King Walk-In Cooler Alarm HIGH SUPERHEAT: Above Upper Limit
HIGH SUPERHEAT is an alarm on the KE2 evaporator control: superheat is above the upper limit. The document gives no repair steps. It usually means the evaporator is not getting enough refrigerant, so watch the box temperature and have a technician check.
Medium: the coil may not be working at full efficiency, though the document describes no shutdown.
- Code
- HIGH SUPERHEAT
- Maker
- Polar King
- Equipment
- Walk-in coolers & freezers
- Applies to
- Polar King walk-in coolers/freezers with KE2 Evaporator Efficiency Evap OEM board (Basic Display / Combo Display)
What does Polar King HIGH SUPERHEAT mean?
Superheat is the number of degrees by which the refrigerant leaving the evaporator is warmer than its boiling point, and the KE2 Evaporator Efficiency board watches it to keep the coil working well. The Alarms Status Menu lists HIGH SUPERHEAT when superheat is above the upper limit. On the Combo Display the name appears; on the Basic Display only a red or yellow light does. The installation instructions state only the trigger and mention the CLEAR ALARMS menu item. They do not give causes or steps. In refrigeration practice, high superheat tends to point to a coil that is starved of refrigerant, for example by a restriction, a low charge or an expansion device that is not opening far enough, but the document does not say this. We note it only to explain why the alarm should not be ignored.
Affected models and control systems
Polar King walk-in coolers and freezers fitted with the KE2 Evaporator Efficiency Evap OEM board, with either the Basic Display or the Combo Display. The alarm is listed in the Alarms Status Menu, which is view only, on page 14 of the KE2 installation instructions.
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
- Red or yellow light on the Basic Display
- HIGH SUPERHEAT on the Combo Display
- Box temperature rising slowly
- Frost only at the start of the coil
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.
- Low refrigerant charge after a slow leak
- A restriction in the liquid line or filter drier
- An expansion device that is not feeding enough refrigerant
- A suction sensor reading that is wrong
Safe checks before calling for service
- Check the box temperature with a thermometer.
- Look at the evaporator without opening it. Note whether frost covers the whole coil or only part.
- Clear the alarm with CLEAR ALARMS and see whether it returns.
- If it returns, write down the box temperature and the frost pattern and arrange service.
How a technician diagnoses HIGH SUPERHEAT
- Read the alarm and the superheat value.
- Check pressures and temperatures with gauges and compare them with the superheat the board shows.
- Check the suction sensor against a reference.
- Look for a restriction, low charge or a feed problem at the expansion device.
- Correct the cause and watch superheat settle within limits.
- Measuring superheat properly needs gauges on the refrigerant circuit and certified handling. Causes such as low charge or a restriction can only be corrected by a refrigeration technician. Adjusting the limits to make the alarm go away can hide a real problem.
How HIGH SUPERHEAT differs from similar codes
HIGH SUPERHEAT is the upper-limit alarm. LOW SUPERHEAT is the lower-limit one, and they point in opposite directions.
Technical reference
- Document
- KE2 Evaporator Efficiency Installation Instructions N.1.1 (posted on polarking.com Downloads as ke2-installation.pdf; authored by KE2 Therm Solutions)
- Edition
- N.1.1 July 2015
- Models / control
- Polar King walk-in coolers/freezers with KE2 Evaporator Efficiency Evap OEM board (Basic Display / Combo Display)
- Section
- Alarms Status Menu (view only), p. 14 (Alarm Status Menu listed p. 13)
- 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 Polar King walk-in cooler & freezer error codes
What is superheat?
It is how much warmer the refrigerant leaving the evaporator is than its boiling point. The board watches it to run the coil properly.
Is HIGH SUPERHEAT an emergency?
The document does not say. Watch the box temperature and protect product if it rises.
Can clearing the alarm solve it?
No, it only clears the stored alarm.
Need help with Polar King HIGH SUPERHEAT?
A technician confirms the cause on site and gives you the price in writing before any work starts.