Yellow ALERT LED 3 flashes — Compressor short cycling

What does ALERT LED 3 flashes Yellow mean?

The compressor is running only for very brief periods. This is a LOCKOUT condition.

• Low refrigerant charge.
• Evaporator blower is not running.
• Evaporator coil is frozen.
• Faulty metering device.
• Condenser coil is dirty.
• Liquid line restriction (e.g., blocked filter drier).
• Intermittent thermostat demand signal.
• System or control board is defective.
• High pressure switch is open (refer to Flash Code 2).

Click steps to track your progress.

1. 1

   Turn off unit power supply and install a lockout tag.

2. 2

   If a low pressure switch is open, check for low refrigerant charge.

3. 3

   Verify the evaporator blower is running.

4. 4

   Inspect the evaporator coil for frost buildup.

5. 5

   Check the condenser coil for cleanliness.

6. 6

   Ensure the thermostat demand signal is stable.