Photoresistive flame detectors for use with Landis & Staefa burner controls, for the supervision of oil flames in the visible light spectrum. The flame detectors are used primarily in connection with burner controls for small burners.

• With this type of flame supervision, the radiation of oil flames in the visible light spectrum is used for generating the flame signal.

• The light-sensitive element is a photoresistor.

• When there is no light, the detector′s resistance is in the MΩrange.

• The resistance drops as the intensity of illumination increases (kΩrange).

• In contrast to the selenium photocell of the RAR... detectors, glowing firebrick in the combustion chamber can be detected.