AHT Cooling Systems E36

What does AHT Cooling Systems E36 mean?

The controller reports that the internal goods room temperature has fallen below its permitted lower alarm threshold. E36 means the cabinet is overcooling — the goods room is colder than the configured minimum alarm level. This risks freezing chilled products and indicates a loss of regulation in the refrigeration control loop, a sensor fault, or an incorrectly set alarm threshold.

Symptoms

• E36 fault code displayed with red LED and buzzer active.
• Goods room temperature reading below the configured low-temperature alarm threshold.
• Chilled products may show frost damage or partial freezing.
• Compressor may be running continuously without cut-out at setpoint.
• Temperature display reads significantly below the normal operating temperature for the cabinet class.

Common causes

• Goods room temperature sensor failed or mislocated, producing a falsely low reading that drives continuous cooling.
• Thermostat or setpoint incorrectly configured — low-temperature alarm threshold set too high relative to setpoint, or setpoint itself set too low.
• EEV stuck in an overfed position or compressor cut-out not functioning, causing continuous overcooling.
• Very low ambient temperature around the cabinet causing the goods room to cool below normal limits.
• Control board fault preventing normal refrigeration cut-out at setpoint.

Diagnostic steps

1. 01

   Assess goods condition

   Check whether products are actually frozen or frost-damaged. Transfer at-risk goods to a correctly rated cabinet. Use a calibrated reference thermometer to verify the actual goods room temperature against the display reading.

2. 02

   Verify temperature setpoint and alarm settings

   Confirm the setpoint has not been inadvertently lowered. Setpoint and alarm threshold adjustments are restricted to authorized staff on the Vento controller — consult AHT IOM Chapter 4 for display operation.

3. 03

   Check goods room sensor

   Inspect the goods room temperature sensor (also monitored under E09) for correct mounting, wiring, and continuity. A failed sensor reading colder than actual temperature will hold the compressor on indefinitely.

4. 04

   Observe compressor cycling

   Determine if the compressor is cutting out normally or running continuously. Continuous compressor operation without cut-out at setpoint points to a control or sensor fault requiring professional diagnosis.

5. 05

   Check ambient conditions

   Verify the store ambient temperature around the cabinet is within the rated range for the device. Unusually cold surroundings can contribute to low goods room temperatures in some cabinet configurations.

6. 06

   Contact AHT service

   If the cause is not a setting error, contact AHT service at 00800/73783248 or www.aht.at/service for sensor replacement or control diagnosis by an authorized technician.

When to call a professional

If E36 is not caused by an incorrect setpoint or alarm threshold, an AHT-authorized technician is needed to diagnose the goods room sensor, EEV, or compressor cut-out circuit. Contact AHT service at 00800/73783248 or www.aht.at/service.