Kolpak Walk-In Cooler Alarm SUCTION TEMP SENSOR: Open or Shorted
SUCTION TEMP SENSOR on a Kolpak walk-in's ArcticFox controller means the suction temperature sensor is shorted or open. Press ENTER to silence it for 1 hour; the alarm sounds again if the condition is not corrected.
Medium: a refrigeration input is not reading, so superheat control cannot be trusted until it is repaired.
- Code
- SUCTION TEMP SENSOR
- Maker
- Kolpak
- Equipment
- Walk-in coolers & freezers
- Applies to
- ArcticFox OEM Controller with Deluxe Display (Kolpak walk-ins)
What does Kolpak SUCTION TEMP SENSOR mean?
The suction temperature sensor measures how warm the refrigerant vapor is as it returns to the compressor. The ArcticFox controller compares it with the suction pressure to calculate superheat, a measure of how well the evaporator is being fed. If the sensor is shorted or open, the controller has no valid reading and shows the text alarm SUCTION TEMP SENSOR in the Alarms menu. The manual gives that definition and one action: press ENTER to silence the alarm for 1 hour while the condition is addressed. The alarm comes back if the system is not corrected by then. It lists no further causes. This is one of four sensor alarms on the same controller, along with PRESSURE SENSOR, AIR TEMP SENSOR and COIL TEMP SENSOR, and each one concerns a different probe.
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
- SUCTION TEMP SENSOR in the Alarms menu
- Alarm repeating after an hour
- Superheat alarms appearing too
- Room temperature varying more than usual
Possible causes
Likely causes — what usually sits behind SUCTION TEMP SENSOR on this control. A technician confirms which one it is before any part is replaced.
- Suction temperature sensor shorted
- Suction temperature sensor open
- Sensor probe knocked loose from its clip on the suction line
- Insulation wet or missing around the sensor, giving unstable readings
- Cable crushed or chafed where it passes the compressor housing
Safe checks before calling for service
- Press ENTER on the display to silence the alarm for 1 hour.
- Check the room temperature with your own thermometer.
- Look for obvious damage to cables near the condensing unit without touching the refrigerant lines.
- Note whether other alarms such as the superheat alarms are shown.
- Call for service and tell them the exact alarm text.
How a technician diagnoses SUCTION TEMP SENSOR
- Read the Alarms menu and the live suction temperature on the controller.
- Inspect the sensor on the suction line and its wiring.
- Measure the sensor's resistance and compare it with a reference thermometer on the line.
- Check the connector at the controller.
- Replace a sensor that tests open or shorted, with insulation refitted properly.
- Check that superheat values return to a sensible range.
- The sensor is strapped to the suction line, which means working around the refrigeration circuit.
- Resistance checks against a reference thermometer require tools and the sensor's table.
- Superheat values only mean something once the sensor is confirmed good.
How SUCTION TEMP SENSOR differs from similar codes
This is the temperature probe on the suction line. PRESSURE SENSOR is the pressure input used with it to work out superheat.
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
Is this the same as AIR TEMP SENSOR?
No. SUCTION TEMP SENSOR is the probe on the suction line, and AIR TEMP SENSOR is the return air probe.
How long does ENTER silence it?
The manual says 1 hour.
Will the room stop cooling?
The manual does not say. Check room temperature and call service.
Need help with Kolpak SUCTION TEMP SENSOR?
A technician confirms the cause on site and gives you the price in writing before any work starts.