Carel AL14

What does Carel AL14 mean?

AL14 on Carel µChiller and pCO chiller controllers indicates that the main condenser fan motor thermal overload protection has tripped. The fan overload device opens when the fan motor draws excessive current — typically due to a mechanical obstruction, a failing motor bearing, or an overvoltage condition — and signals the controller to raise the alarm. Compressor operation continues but condensing performance is reduced.

Symptoms

• AL14 displayed on the Carel controller.
• Main condenser fan has stopped or is running intermittently.
• Condenser (high-side) pressure may rise due to reduced airflow.
• The thermal overload relay on the fan motor control panel has tripped.

Common causes

• Fan motor bearing seized or worn, increasing motor current draw.
• Foreign object (leaves, debris) lodged in the fan blades causing mechanical resistance.
• Motor windings partially failed, drawing elevated current.
• Supply voltage outside rated tolerance causing motor overheating.
• Thermal overload relay incorrectly sized or drifted out of calibration.

Diagnostic steps

1. 01

   Isolate the fan and inspect for obstructions

   Lock out/tag out the fan circuit. Remove any debris lodged in the blade assembly or housing that could cause mechanical binding.

2. 02

   Attempt to rotate the fan blade by hand

   With power off, try rotating the fan blade manually. Stiff, rough, or seized rotation indicates a bearing failure requiring motor replacement.

3. 03

   Check supply voltage at the fan motor

   Measure all three phases at the motor terminals. Voltage imbalance greater than 2% or voltage outside the motor's rated range causes overheating.

4. 04

   Measure motor running current after reset

   Reset the overload relay and start the fan. Immediately measure running current with a clamp meter. Current above the motor nameplate FLA confirms a winding or mechanical fault.

5. 05

   Reset the overload relay

   Allow the motor to cool (15 minutes minimum), then manually reset the overload relay. Verify the fan restarts and AL14 clears at the controller.

When to call a professional

Replace a seized or electrically failed fan motor with a licensed electrical contractor or refrigeration engineer who can work on the live panel safely. Repeated AL14 after motor replacement indicates a supply voltage quality issue or incorrect overload sizing that requires electrical investigation beyond standard field maintenance.