Furnace Error Codes

A furnace error code is a pattern of LED blinks or a number on the control board that names the fault, such as a pressure switch, ignition failure or flame loss. Read the code before you reset power, because a reset clears the stored fault.

These guides cover Carrier, Goodman, Trane and Lennox furnace codes. Each explains the meaning, safe homeowner checks like the filter, condensate drain and vent pipes, the reset steps and the point where a licensed HVAC technician is needed. Gas safety comes first in every article, and code meanings are checked against the manufacturer’s literature.