HVAC Code Lookup

Lennox Furnace Code E271

Soft lockout

Soft lockout. The furnace used up its ignition retries and the last attempt failed because the pressure switch opened.

Manual wording: “Soft lockout - Exceeded maximum number of retries. Last retry failed due to the pressure switch opening.”

Documented for: EL296UHE and SLP98UHV series

Likely causes, most common first

  1. Blocked or restricted intake or exhaust vent pipe
  2. Plugged condensate drain or trap
  3. Loose or wet pressure switch tubing
  4. Failing combustion air inducer

What you can safely check yourself

  • Check the outdoor intake and exhaust pipes for snow, ice or debris
  • Check the condensate drain line and trap for a clog
  • Turn the furnace power switch off for 30 seconds and back on once, one time only

When to call a technician

Same diagnosis as E223: the manual calls for measuring pressure switch closing pressure and inspecting the vent and inducer for restriction. Have a technician do it.

A Lennox furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Other Lennox codes