Polar King Walk-In Cooler Alarm DOOR SWITCH: Door Open and Room Warm
DOOR SWITCH is an alarm on the KE2 evaporator control: the door is open and the room is 5 degrees above ROOM TEMP plus AIR TEMP DIFF for the DOOR ALARM DELAY time. The document gives no repair steps. Close the door fully and check the box temperature.
Medium: the door is open while the box warms, which risks product temperature.
- Code
- DOOR SWITCH
- 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 DOOR SWITCH mean?
This alarm combines two facts. The KE2 Evaporator Efficiency board sees the door as open, and the room temperature is 5 degrees above ROOM TEMP plus AIR TEMP DIFF, and both stay true for the DOOR ALARM DELAY time. Then the Alarms Status Menu lists DOOR SWITCH. The Combo Display shows the name; the Basic Display shows a red or yellow light. The installation instructions state the trigger and mention the CLEAR ALARMS menu item for clearing, and give no cause or repair. Most often it means a door was left open during a delivery or stocking. It can also appear if the switch tells the board the door is open when it is shut. The alarm alone cannot tell the two situations apart, which is why you should look at the door first.
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
- DOOR SWITCH on the Combo Display
- Door ajar or not latching
- Box warming
Possible causes
Likely causes — what usually sits behind DOOR SWITCH on this control. A technician confirms which one it is before any part is replaced.
- A door propped open or stuck on a cart or a pallet
- A door latch or closer that no longer pulls the door shut
- A door switch stuck in the open position by ice or grime
- A switch wire cut at the door frame
Safe checks before calling for service
- Make sure the door is closed and latched.
- Look at the door switch area for ice or debris without taking anything apart.
- Check the box temperature with a thermometer.
- Clear the alarm with CLEAR ALARMS. If DOOR SWITCH returns with the door shut, record it and arrange service.
How a technician diagnoses DOOR SWITCH
- Read the alarm and the DOOR ALARM DELAY setting.
- Check the door, latch, closer and gasket.
- Test the door switch for continuity in both door positions.
- Check the wiring to the board.
- Replace the switch if it fails the meter test.
- The door switch and its cable sit in the door frame next to heater cable and line voltage. Telling a stuck switch from a door that really is open needs a meter and a close look at the door hardware. Door closer and hinge adjustment on a heavy walk-in door should be done by a technician.
How DOOR SWITCH differs from similar codes
DOOR SWITCH needs the door to be open as well as the room to be warm. HIGH AIR TEMP does not depend on the door.
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
Why did DOOR SWITCH go off when I stocked the cooler?
The door was open and the box warmed by 5 degrees for longer than the delay.
What if the door is closed and the alarm remains?
The switch may be stuck or its wire damaged, and a technician should test it.
Can I clear it?
Yes, with CLEAR ALARMS, but the alarm returns if the door or switch is still the problem.
Need help with Polar King DOOR SWITCH?
A technician confirms the cause on site and gives you the price in writing before any work starts.