Code 81 — Thermal lockout in low stage (4 hrs)

What does 81 mean?

The low stage compressor has experienced a thermal lockout, meaning it has overheated and shut down. It will remain locked out for 4 hours.

• Low refrigerant charge
• Overheating due to poor airflow
• Faulty low stage compressor
• High ambient temperatures

Click steps to track your progress.

1. 1

   Ensure adequate airflow to the outdoor unit.

2. 2

   Check for any obstructions around the outdoor unit.

3. 3

   Allow the system the full 4-hour lockout period before attempting to restart.

4. 4

   Contact an HVAC technician if the issue repeats.