Ako F4 Error Code

What does Ako F4 mean?

F4 defines the fan start-up delay time after defrost (in minutes). After the defrost drip-off period (d9) ends, the controller waits for the F4 duration before restarting the evaporator fans. This delay allows any remaining water droplets on the evaporator fins to freeze in place rather than being projected into the cold room by the fans. This is a commissioning parameter, not a fault code.

Symptoms

• Fans remain off for the F4 delay period immediately after each defrost cycle completes.
• If F4 is set too long, cold room temperature recovers more slowly after defrost.
• If F4 is set to 0 or too short, fans restart while drip water is still present, projecting droplets into the cold room.
• Frost or ice deposits on cold room walls or product near the evaporator discharge may indicate F4 is too short.

Common causes

• F4 parameter set to 0 or a very short duration during commissioning — droplets are projected before freezing.
• F4 set too long for the application — cold room recovery is unnecessarily delayed after each defrost.
• Factory default F4 value inappropriate for the specific installation's evaporator type and heat load.

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Diagnostic steps

1. Determine the appropriate F4 value for the installation

   Typical F4 values range from 0 to 10 minutes depending on evaporator size and heat load. Consult the AKO commissioning guide for the application type (cold room vs. display case).

2. Check the current F4 value

   Enter the parameter menu and read the current F4 setting. Compare it against the commissioning specification.

3. Observe post-defrost behavior

   After a defrost cycle completes, observe whether water droplets are visible on the evaporator when fans restart. If droplets are present, increase F4 to provide additional freezing time.

4. Adjust F4 if incorrect

   Set F4 to the correct value for the installation. Save the parameter and allow the next defrost cycle to complete to verify the change has the desired effect.

5. Document the F4 setting

   Record the confirmed F4 value in the commissioning record for future reference during maintenance.

When to call a professional

Call a licensed refrigeration technician if defrost is consistently incomplete (ice remains after defrost) or if the post-defrost evaporator state suggests a heater or defrost termination issue that goes beyond F4 adjustment. A technician is also needed if defrost cycle length and drip-off time require comprehensive re-commissioning of d2, d3, d4, d9, F3, and F4 together.