System Diagnosis
Limit Switch Open. The furnace has overheated or the rollout switch has tripped.
Lennox | LED Status Codes (DS1 & DS2)
Error Code On / Slow Flash
Troubleshooting guide for the Lennox LED Status Codes (DS1 & DS2) system fault On / Slow Flash.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
Potential Causes & Solutions
- Dirty filter, blocked vents, bad blower motor, restricted airflow.
Diagnose with Confidence
Use the ACLogics AI assistant to walk through this error code step-by-step.
Included in Diagnosis Workflow
Ask
Upload nameplate & symptoms
Diagnose
AI identifies error On / Slow Flash
Report
Generate professional PDF