Furnace Flame Sensor (Direct Replacement for Carrier, Bryant, Payne, Day & Night)
Updated June 17, 2026
This is a direct replacement flame sensor designed for use in Carrier, Bryant, Payne, Day & Night gas furnaces. It monitors the burner flame to ensure safe operation; if no flame is detected, the sensor signals the gas valve to close, preventing unburned gas from accumulating.
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How It Works
The flame sensor is a metal rod that sits in the burner flame. When heated by the flame, it generates a small electrical current (microamps) that is detected by the furnace control board. This current confirms the presence of a flame, allowing the gas valve to remain open. If the flame goes out, the current drops and the valve closes.
Common Failure Symptoms
A failing flame sensor may cause the furnace to ignite but then shut off after a few seconds (short cycling), or fail to ignite at all. The furnace may lock out after repeated failed attempts. Often, the sensor becomes coated with soot or oxidation, reducing its ability to conduct current.
Installation Notes
This is a direct replacement part. Installation typically involves removing the old sensor (usually one screw), disconnecting the wire, and installing the new sensor. Ensure the furnace is off and power disconnected. Clean the new sensor with a mild abrasive (e.g., fine steel wool) before installation to remove any protective coating. Do not touch the sensor with bare hands after cleaning; oils can cause hot spots.
