Lennox Heat Pump Error Code Green ON / Red OFF

The Green ON / Red OFF LED pattern signals a high pressure lockout. The heat pump's high pressure safety switch tripped five times during a single demand cycle, causing the control board to shut down the compressor to prevent damage. The system will remain locked out until the underlying cause is corrected and the fault is cleared. A technician should check system charge, operating pressures, and airflow before restarting the unit.

Cycling power may temporarily clear the lockout and allow the unit to restart, but if the root cause of the high pressure condition is not corrected, the switch will trip again and the system will return to lockout after five more trips. Resetting without fixing the underlying problem risks accelerating compressor wear and could cause permanent damage.

Repair costs vary widely depending on the root cause. Cleaning a dirty coil or clearing an airflow obstruction might cost between $75 and $200 for a service call. Refrigerant adjustment, expansion device replacement, or a condenser fan motor replacement can range from $200 to $800 or more depending on parts and labor rates in your area. Compressor replacement, if damage has already occurred, can exceed $1,500 to $3,000.

Some causes, such as a visibly dirty outdoor coil or blocked airflow around the unit, can be addressed by a knowledgeable homeowner. However, diagnosing and correcting refrigerant charge, expansion device problems, or fan motor failures requires EPA-certified refrigerant handling and specialized pressure gauges. It is safest to have a licensed HVAC technician perform the full diagnosis to avoid compressor damage.

No. The lockout exists specifically to prevent the compressor from operating under dangerous pressure conditions. Repeatedly resetting and running the unit without addressing the cause can lead to compressor valve damage or complete compressor failure, which is a much more expensive repair. The unit should remain off until a qualified technician has diagnosed and corrected the fault.