What does Lennox code 271 mean?
Lennox furnace code 271 means the furnace exceeded its ignition retries after the pressure switch opened on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Lennox code 271?
- A blocked intake or exhaust vent
- A restricted condensate drain or pressure hose
- A weak inducer motor or pressure switch
Can I troubleshoot Lennox code 271?
- With the furnace off, check outdoor intake and exhaust openings for snow, ice, leaves, or nests.
- Replace a visibly dirty air filter, restore power once, and note whether the code returns.
How much does Lennox code 271 cost to fix?
A pressure switch replacement typically costs between $175 and $900 nationally.
When should I call a technician?
Call a technician if the vent is clear and the pressure-switch code returns; combustion-air testing requires instruments.
Symptoms this code causes
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.