Error 99 — High Torque Lockout

What does 99 mean?

The system has entered a lockout state due to high torque. This can be caused by various factors including operating outside normal ranges, restrictions, overcharge, non-condensibles, or issues with service valves or airflow.

• Outside Normal Operating Range (improper load calculation, system match issue)
• Restriction due to debris (leading to overcharge in cooling mode)
• Restriction in EXV (plus Long Line Application, leading to overcharge in cooling mode)
• Overcharged System
• Non-condensibles leading to high load
• Restriction in Filter Drier (plus Long Line Application and filter drier on Outdoor Unit)
• Service Valve left closed (Liquid or Vapor)
• Cool Outdoor Airflow too low or off
• Restriction in EXV plus Overcharge
• Furnace stuck on (in Furnace plus Heat pump application)
• Expansion Orifice Restriction
• Indoor Airflow too low or off
• Reversing Valve Stuck in Cooling

Click steps to track your progress.

1. 1

   Ensure all service valves (Liquid or Vapor) are fully open.

2. 2

   Check the Outdoor Coil for clogging (ice or debris) and clean or de-ice if necessary. Verify the Outdoor fan motor is working.

3. 3

   Check the Indoor coil for clogging (ice or debris) and clean or de-ice if necessary. Verify the Indoor fan motor is working.

4. 4

   If the issue persists, contact a qualified technician. This fault often requires detailed system inspection and cleaning, charge verification, or component troubleshooting.