Polar King Walk-In Cooler Alarm HIGH AIR TEMP: Room Too Warm
HIGH AIR TEMP is an alarm on the KE2 evaporator control: the room temperature has stayed above a limit for longer than the alarm delay. The document gives no repair steps. Check the box with a thermometer, make sure the door is closed and protect product if it keeps rising.
High: the walk-in has stayed above its temperature limit and stored product is at risk.
- Code
- HIGH AIR TEMP
- 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 AIR TEMP mean?
This alarm is a timed temperature check. The KE2 Evaporator Efficiency board adds ROOM TEMP, the air temperature difference setting (AIR TEMP DIFF) and the HIGH TEMP ALARM OFFSET to make a threshold. If the room temperature stays above that threshold for longer than the HIGH TEMP ALARM DELAY, the Alarms Status Menu lists HIGH AIR TEMP. The Combo Display shows the name; the Basic Display shows a red or yellow light. Because of the delay, a door opened briefly or a warm delivery should not set it off, so when it does appear the box has been warm for a while. The document lists the trigger only, gives no causes and no repair steps, and mentions the CLEAR ALARMS menu item for clearing. The alarm tells you the box is warm but not why, which is for a technician to find.
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 AIR TEMP in the Combo Display alarm list
- Walk-in warm to the touch
- Product at the front of the shelves feeling warm
Possible causes
Likely causes — what usually sits behind HIGH AIR TEMP on this control. A technician confirms which one it is before any part is replaced.
- A door left ajar or a strip curtain torn so warm air flows in
- A condensing unit running hot in a hot summer machine room
- An evaporator coil iced over and passing little air
- A compressor that has stopped or cycles off on a safety
Safe checks before calling for service
- Check that the walk-in door is fully closed and the strip curtains hang properly.
- Place a thermometer in the box and check it over an hour.
- Check that no stock blocks the evaporator fan or the air path.
- Clear the alarm with CLEAR ALARMS. If HIGH AIR TEMP returns, move product that must stay cold and arrange service.
How a technician diagnoses HIGH AIR TEMP
- Read the alarm, the room temperature and the alarm settings.
- Check the door, gasket and heater cable for leaks and heat.
- Check that the compressor and condenser fan are running and the coil is clean.
- Check evaporator fans and the coil for ice.
- Check refrigerant pressures with gauges and find the cause of lost capacity.
- Checking the compressor and condenser fan means working at live 208-240 V wiring. Refrigerant pressures require gauges and certified handling. Food safety decisions for the product also depend on a reliable record of how warm the box got.
How HIGH AIR TEMP differs from similar codes
HIGH AIR TEMP is a timed alarm based on the room temperature; DOOR SWITCH is a separate alarm that depends on the door being open.
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
How long does the box have to be warm before this alarm sounds?
Longer than the HIGH TEMP ALARM DELAY, which is a setting on the board. The document does not give a number.
Should I throw out the food?
That depends on how warm the box got and for how long. Use a thermometer and your food safety rules.
Is this alarm the same as DOOR SWITCH?
No. DOOR SWITCH needs the door to be open as well as the room being warm.
Need help with Polar King HIGH AIR TEMP?
A technician confirms the cause on site and gives you the price in writing before any work starts.