E221 (Red ON, Green Blink, Yellow OFF) — Outdoor temperature sensor error

What does E221 mean?

The outdoor unit's PCB LED displays E221 when there is an open or short circuit detected in the outdoor temperature sensor. This prevents the system from accurately reading the ambient outdoor temperature.

• Damaged outdoor temperature sensor
• Loose or corroded sensor wiring connection
• Faulty outdoor PCB

Click steps to track your progress.

1. 1

   Turn off the main power to the outdoor unit at the circuit breaker.

2. 2

   Visually inspect the outdoor temperature sensor and its wiring for any signs of damage or loose connections.

3. 3

   Ensure the sensor is properly positioned and not obstructed.

4. 4

   Restore power to the unit. If the error persists, contact a qualified technician to test or replace the sensor.