Nor-Lake LogiTemp Walk-In Error Code A3A: AUX3 Sensor Shorted or Open
A3A signals that the AUX3 temperature sensor is shorted or open on a Nor-Lake walk-in cooler or freezer with a Split-Pak system and LogiTemp control. Anything that relies on that sensor works without it. Note the code and LED color, check the box with a thermometer and call us if A3A returns.
Medium: one extra sensor is lost, while the main temperature control keeps running.
- Code
- A3A
- Maker
- Nor-Lake
- Equipment
- Walk-in coolers & freezers
- Applies to
- LogiTemp / KE2 Evap OEM (Split-Pak systems, A1 refrigerants)
What does Nor-Lake error code A3A mean?
AUX3 is the third of the auxiliary sensor inputs on the LogiTemp controller. These inputs can watch extra points chosen when the system was installed, such as a second probe, an extra alarm point or a control function. The controller expects each used input to return a reasonable temperature. When the reading is lost, either because the sensor circuit is shorted or because it is open, the controller flags it on the Basic Display as A3A. The main temperature control of the box keeps working, so the cooler or freezer generally stays cold, but any extra alarm or control that relied on the AUX3 reading is running without it. The problem can sit in the sensor, in the wire run and connector to the board, or in the input itself. Moisture in a connector inside a cold box is worth special mention: it can short the sensor lines for a while and then dry out or freeze, which is why the alarm may come and go.
Affected models and control systems
This applies to the LogiTemp / KE2 Evap OEM controller on Nor-Lake Split-Pak systems with A1 refrigerants, in 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
- A3A on the Basic Display
- An alarm LED showing on the controller
- Box temperature normal on a thermometer
- Extra alarm or control based on AUX3 not working
Possible causes
Listed in Nor-Lake's documentation
- The sensor wired to AUX3
- The wire run and connector to the board
- The AUX3 input on the controller
- Moisture in a connector inside a cold box
Other likely causes — what usually sits behind error code A3A on this control. A technician confirms which one it is before any part is replaced.
- Frost bridging the connector pins in a low-temperature box
- Cable run crushed under a shelf bracket or cable tie
- Sensor installed for a function that was later removed, leaving the input open
Safe checks before calling for service
- Write down the code and the LED color showing.
- Check the walk-in with a thermometer to see whether the box itself is holding temperature.
- Close the door fully and clear anything blocking it.
- Call us to schedule service if A3A returns after the display has been left to settle.
How a technician diagnoses error code A3A
- Read A3A and learn what AUX3 was set up to watch.
- Compare the sensor reading with a reference thermometer.
- Inspect the connector for moisture or ice and the wire for damage.
- Measure the sensor resistance at the board and at the sensor.
- Replace the sensor, wire or input only after the result.
- Connectors and wiring inside a cold box are wet and icy, which makes shock and damage risks real.
- The board in the control area carries live voltage.
- The sensor's resistance must be compared with a temperature chart, which a technician carries.
How error code A3A differs from similar codes
A1A and A2A report the other two auxiliary inputs. A3A is only about AUX3.
Technical reference
- Document
- LogiTemp Electronic Controller System Operations Manual (171527 Rev. A), Alarms & Notifications List pp. 47-51
- Edition
- 171527 Rev. A, 2025 (Refrigerated Solutions Group)
- Models / control
- LogiTemp / KE2 Evap OEM (Split-Pak systems, A1 refrigerants)
- Section
- Alarms & Notifications List, printed pp. 48-52; Troubleshooting Tables from p. 52
- 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 Nor-Lake walk-in cooler & freezer error codes
Is the walk-in safe with A3A showing?
The main control is separate, but keep a thermometer in the box and watch it until we have checked.
Why does A3A come and go?
Moisture or ice in a connector can open and close the circuit as temperatures change.
Does A3A need an urgent visit?
Not usually, unless the box is warming or the AUX3 function is critical to your product.
Need help with Nor-Lake error code A3A?
A technician confirms the cause on site and gives you the price in writing before any work starts.