Honeywell Flicker detector IRD1020.1 16552U

This is an industrial flame sensor, specifically a flicker detector, used for flame proving in gas and oil burners. It operates by infrared flicker detection, monitoring the characteristic flicker of a radiating flame. The detector is mounted with a direct line of sight to the flame, often through a sight tube or sealed window. When flame is present, it sends a signal to the burner control during the ignition sequence.

Parts of this type are selected by their spectral response range, response time, cable length and connector type, and the mounting sleeve or bracket. The detector must be aligned with the flame and the sight path must be free of obstruction. Before ordering, compare these parameters with the existing wiring and physical installation. Replacement units should be matched to the burner control's requirements.

Typical failures include a contaminated or fogged window that reduces sensitivity, an aged sensing element causing weak or intermittent signals, and damaged sheath or cable. When the detector fails, the burner control may lock out and shut down fuel supply because it does not receive a flame-confirmation signal. Checking involves ensuring the sight path is clean and the detector is correctly aligned.