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.

The flame detectors are used for the supervision of gas flames, yellow- or blue-burning oil flames and for ignition spark proving.

• With this type of flame supervision, the UV radiation emitted by gas or oil flames is used to generate the flame signal.

• The radiation detector consists of a UV-sensitive cell with 2 electrodes, which ignite when illuminated with radiation in the 190...270 nm range of the spectrum, thereby triggering a current in the flame detector circuit.

• The UV cell does not respond to glowing firebrick in the combustion chamber, daylight or light from the boiler room illumination.