Carel AL36

What does Carel AL36 mean?

AL36 is the Built-in Humidifier Operating Hour Threshold alarm on the Carel Standard Air-conditioner (030221426). The integrated humidifier has accumulated the configured number of operating hours since the last maintenance reset, signaling that scheduled maintenance — cylinder inspection, cleaning, or replacement — is due. This is a warning alarm; the humidifier continues to operate.

Symptoms

• AL36 displayed on the controller as a maintenance warning.
• Humidifier continues operating normally — no shutdown occurs.
• Hour counter has reached the programmed maintenance threshold.
• Alarm relay may activate per configured alarm relay assignment.

Common causes

• Humidifier has reached the programmed operating hour maintenance interval.
• Hour counter was not reset at the previous maintenance service.
• High water conductivity or poor water quality accelerating scale buildup, making more frequent service necessary.

Diagnostic steps

1. 01

   Inspect the humidifier cylinder

   Remove and inspect the cylinder electrodes for scale buildup. Heavily scaled electrodes require cleaning or cylinder replacement even if the unit is still producing steam.

2. 02

   Clean or replace the cylinder

   For openable cylinders, descale using the procedure in the service manual. For disposable cylinders with significant electrode wear or heavy scale, replace with a new cylinder.

3. 03

   Inspect the drain valve and level sensor

   Clean the drain valve seat and strainer. Remove and clean the conductivity electrodes on the level sensor assembly to ensure accurate water level control.

4. 04

   Reset the hour counter parameter

   After completing maintenance, navigate to the hour counter reset parameter in the controller programming menu and reset it. AL36 will not clear until the counter is reset manually.

When to call a professional

Contact a qualified HVAC technician if the humidifier shows AL36 together with active alarms such as high current, drain failure, or fill failure, indicating a more serious maintenance condition. If hour intervals are shorter than expected due to poor water quality, a water treatment specialist should assess the supply water chemistry.