Common furnace repairs: an overview

Furnace problems are easier to understand when you start with the symptom: no heat, cold air from the vents, short cycling, repeated shutdowns, unusual noise, or uneven rooms. Use the detailed guides below for the symptom-specific next step. Common parts include igniters, flame sensors, capacitors, blower motors, inducer motors, pressure switches, limit controls, thermostats, and control boards, but the same symptom can have several causes. A part should not be replaced solely because it is commonly associated with a complaint. Ask what was tested, whether the repair addresses the cause, whether the system is safe to operate, and what warranty applies.