What does Lennox code 274 mean?
Lennox furnace code 274 means the furnace exceeded its recycle limit after the limit circuit opened or stayed open too long on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Lennox code 274?
- A dirty or overly restrictive air filter
- Closed or blocked supply and return vents
- A blower, limit switch, or airflow problem
Can I troubleshoot Lennox code 274?
- Turn the furnace off and replace a dirty filter with the size and type specified for the system.
- Open all supply registers and make sure return grilles are not blocked before trying one reset.
How much does Lennox code 274 cost to fix?
A limit switch replacement typically costs between $150 and $750 nationally.
When should I call a technician?
Call a technician if the limit code returns; repeated overheating can damage the furnace.
Sources and model scope
Fault codes vary by model and control board. Confirm the diagnostic chart inside your furnace panel or the official manual before acting.
Scope used here: Lennox integrated controls covered by installation instructions 508001-02D.
- Lennox Industries: Installation Instructions — Integrated Control Diagnostic Codes
508001-02D · Lennox furnaces explicitly covered by installation instructions 508001-02D; not a universal Lennox code list.
Compiled by Warmlo Editorial · Reviewed August 2026
This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.