Lennox Landmark Error E124

High Discharge Temperature

Compressor discharge thermistor exceeded safe operating limit.

Verify condenser airflow and inspect for non-condensables or overcharge conditions.

⚠️ Always disconnect power before servicing.

Need the full wiring diagram?

Step 1 is just the start. HVAC Hero reads the full Lennox manual for you.

Free 7-day trial. No credit card required for demo.