Carel AL38

What does Carel AL38 mean?

AL38 is the Condenser Fan 1 Thermal Overload alarm on the Carel Standard Air-conditioner (030221426). The thermal overload protection relay on the first condenser fan motor has tripped, cutting power to that fan. With reduced condenser airflow, condensing pressure rises and cooling capacity drops. The controller logs AL38 and disables Condenser Fan 1.

Symptoms

• Condenser Fan 1 stops running immediately.
• AL38 displayed on the controller with buzzer active.
• Condensing pressure may rise progressively on circuit 1 as the condenser is partially unloaded.
• Thermal overload relay in the fan motor electrical panel is tripped.

Common causes

• Condenser fan motor thermal overload relay tripped from sustained overcurrent.
• Fan motor bearings seizing or worn, increasing motor load and current draw.
• Condenser fan blade damaged or blocked, causing the motor to work harder.
• Phase imbalance or voltage unbalance on the fan motor power supply.
• Thermal overload relay set current too low for the actual motor nameplate FLA.

Diagnostic steps

1. 01

   Allow fan motor to cool and reset the overload relay

   Wait 15 minutes for the motor to cool. Locate the thermal overload relay in the electrical panel and press the reset button. Do not attempt multiple rapid resets, which can mask a serious fault.

2. 02

   Inspect the fan blade for damage or obstruction

   Check the condenser fan blade for cracks, missing sections, or debris lodged between the blade and fan guard. An unbalanced or blocked blade increases motor current.

3. 03

   Check motor bearing condition

   With the motor de-energized, attempt to rotate the fan shaft by hand. Resistance or roughness indicates worn or seized bearings. Replace motor bearings or the fan motor assembly.

4. 04

   Measure motor current on all phases

   After resetting the overload, clamp-meter the motor on all three phases while running. Current imbalance above 5% between phases indicates a supply voltage problem or failing motor winding.

5. 05

   Verify overload relay set current

   Confirm the overload relay is set at the motor nameplate FLA. An undersized setting causes repeated nuisance trips under normal operation.

When to call a professional

Call a licensed electrician or refrigeration technician if AL38 trips repeatedly after relay reset, if bearing replacement is required, or if voltage unbalance is detected at the motor terminals. Operating a system with a failed condenser fan for extended periods risks high-pressure trips and compressor damage.