Furnace Error Codes and What They Mean

Red Light Is Blinking On York Furnace? (Possible Causes & Fixes)

Is your furnace cycling on and off or failing to stay lit? One of the most common reasons for furnace malfunction is a dirty flame sensor. This small, often L-shaped metal rod plays a critical role in your heating system's safety. Its job is to detect whether a flame is present when the gas valve is open. If the sensor is coated in oxidation or "gunked up" with soot and debris, it won't be able to send the necessary signal to the control board, causing your furnace to shut down almost immediatel