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Error code · Kolpak · Walk-in coolers & freezers

Kolpak Walk-In Cooler Error Code AUX1 SENSOR: Main AUX1 Shorted or Open

AUX1 SENSOR means the Main AUX1 input is set to a temperature input and is shorted or open. The controller cannot read a temperature from it. Press ENTER to silence the alarm for one hour and have the sensor and wiring checked.

Medium · inspection needed

Low: one auxiliary reading is lost, and the main room controls keep working.

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Code
AUX1 SENSOR
Maker
Kolpak
Equipment
Walk-in coolers & freezers
Applies to
ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)

What does Kolpak error code AUX1 SENSOR mean?

The Main board of the ArcticFox controller has auxiliary inputs that can be set to read a temperature sensor. When AUX1 is set that way, the controller measures the sensor's resistance and converts it to a temperature. A shorted input reads almost no resistance. An open input reads none at all because the circuit is broken. Neither is a value a working sensor produces, so the controller flags it and posts the text alarm AUX1 SENSOR in the Alarms menu. The check is continuous. The alarm describes the sensor circuit, not the temperature being measured, so the room may be perfectly normal. Anything that depends on AUX1 for temperature, such as a monitoring function, cannot work until the input reads properly. The alarm sounds again after the one-hour silence if the sensor circuit is not repaired.

Affected models and control systems

ArcticFox OEM Controller with Deluxe Display on Kolpak walk-ins. This is the Main board AUX1 input, listed in the Alarms menu on page 16. The Display has its own alarm for its AUX inputs.

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

  • AUX1 SENSOR text in the Alarms menu
  • Audible alarm from the display
  • No temperature reading for the AUX1 input
  • Monitoring tied to AUX1 not working

Possible causes

Likely causes — what usually sits behind error code AUX1 SENSOR on this control. A technician confirms which one it is before any part is replaced.

  • Temperature sensor on AUX1 disconnected or its wire broken
  • Sensor cable crushed or shorted against a metal edge
  • Moisture or corrosion inside the sensor connection
  • AUX1 set to a temperature input when no sensor is installed

Safe checks before calling for service

✓ What an operator can do
  1. Press ENTER to silence the alarm. It stays quiet for 1 hour and returns if the sensor circuit is not repaired.
  2. Look at any visible sensor cable for damage. Do not pull, cut or unplug anything.
  3. Note whether the alarm started after a cleaning, a delivery, or a change to shelving.
  4. Give the technician the exact text AUX1 SENSOR and what the sensor is meant to measure, if known.

How a technician diagnoses error code AUX1 SENSOR

  1. Check that AUX1 IN MODE is a temperature input.
  2. Find the sensor and inspect its cable and connector for damage and moisture.
  3. Measure the sensor's resistance and compare with its chart, and test the cable for continuity and shorts.
  4. Replace the sensor or repair the wire, then confirm a normal temperature reading.
! Leave this to a technician
  • Sensor terminals are inside the controller enclosure, which carries line voltage.
  • Separating a shorted sensor from an open wire takes meter readings against a resistance chart.
  • Changing the input mode alters alarms and must follow the installation record.

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.

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AUX1 SENSORQuestions about Kolpak error code AUX1 SENSOR
Does AUX1 SENSOR mean the room is too warm or cold?

No. It reports a bad sensor circuit, not a bad temperature.

Can I pull the sensor out to see if it is loose?

Please leave it. Removing a sensor leaves an open circuit and the alarm stays on.

Is there a matching Display alarm?

Yes. The Display inputs use DISPLAY AUX2 SENSOR and DISPLAY AUX3 SENSOR, while the Main inputs use AUX1, AUX2 and AUX3 SENSOR.

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