Honeywell photo resistor 51001

This is a flame sensor from Honeywell for burner flame detection. It operates on a 24 V supply and uses a photo resistor sensing element that responds to infrared radiation. The housing is made of plastic and metal, and the sensor is rated for ambient temperatures from -20 to 80 °C. With an IP65 ingress protection rating, it is suitable for dusty or damp environments. Its compact size and convenient connection interface simplify installation. It is designed for mounting in a sight tube or socket, and its response time is less than 1 second.

Photo-resistor flame sensors are chosen by detection principle and spectral range; they must align with the flame in a sight tube or socket. Before ordering, verify the mounting sleeve dimensions and the connector style to match the burner control. The adapter provides the mechanical interface and electrical connection between the sensing element and the control box. Confirm that the mounting form and connector match the existing installation.

Common failure modes include a contaminated optical window and an aged cell that switches poorly. Symptoms include a gradual signal degradation and intermittent lockouts. Before replacing the sensor, inspect the sight tube for soot or debris and verify that the cable and connector are intact.