Ako E23

What does Ako E23 mean?

E23 is the AKO-16526 equivalent of E11 but applies to probe S3 on a dual-evaporator configuration. It signals that S3 (the second evaporator probe) is reading a temperature similar to S1 (the cold-room probe), providing insufficient differential for the SELFDRIVE system to calculate the second evaporator's performance. The fault suspends SELFDRIVE optimization for that evaporator circuit.

Symptoms

• E23 appears on the display.
• SELFDRIVE calibration for the second evaporator is suspended.
• Controller falls back to standard regulation for the second evaporator circuit.
• Alarm relay activates.
• Temperature differential between S1 and S3 is abnormally small.

Common causes

• Probe S3 incorrectly positioned on the second evaporator — reading ambient rather than coil temperature (most common).
• Second evaporator heavily iced, insulating S3 from the coil.
• S1 and S3 probes swapped during installation or after a service visit.
• Refrigerant shortage causing the second evaporator to warm up toward cold-room temperature.
• Blocked airflow over the second evaporator reducing the temperature differential.

Diagnostic steps

1. 01

   Verify probe S3 position on the second evaporator coil

   Confirm S3 is properly clipped to the second evaporator coil at the designated measurement point. The probe must contact the coil, not hang in return air.

2. 02

   Check that S1 and S3 are not swapped

   Trace both probe cables to their controller terminals. S1 monitors cold-room air and S3 monitors the second evaporator coil. Swap them back if incorrectly connected.

3. 03

   Inspect the second evaporator for ice blockage

   Check for heavy frost insulating S3. If present, initiate a manual defrost on the second evaporator and confirm the temperature differential increases after defrost.

4. 04

   Assess refrigerant distribution to the second evaporator

   Observe suction line temperatures at both evaporators. If the second evaporator's suction line is noticeably warmer than the first, the expansion valve feeding the second circuit may require adjustment.

5. 05

   Restart SELFDRIVE calibration for the second evaporator

   After restoring the temperature differential, follow the AKO manual procedure to re-enter SELFDRIVE calibration for the second evaporator. Verify E23 clears.

When to call a professional

Call a licensed refrigeration technician if E23 persists after correcting probe positions and clearing ice, as an inadequate temperature differential across the second evaporator indicates a refrigerant distribution problem requiring pressure measurements and potentially expansion valve adjustment or refrigerant handling.