Siemens UV cell 450240650

This Siemens UV cell, SKU 450240650, is a sensor component that functions as a flame detector for oil-fired or industrial burners. It operates on the principle of detecting ultraviolet radiation emitted by the flame. In the flame-proving stage, the burner control expects a UV signal within the specified safety time after fuel opens; if the cell does not detect the radiation, the control goes to lockout.

When selecting a replacement UV cell for such burners, check the spectral sensitivity range to ensure it matches the flame's ultraviolet output. The signal cable length and connector type, often a coaxial or two-pin plug, must be compatible with the existing burner control wiring. Some control circuits require a specific impedance or a shielded cable, so verify the input specification before ordering. Mounting requires a clear, unobstructed line of sight to the flame, and the viewing window must be kept clean.

Common failure modes of UV cells include a slow response or a weak signal due to tube ageing or contamination of the lens. If the cell cannot detect the ultraviolet radiation from the flame, the burner control will lock out during the safety sequence. Intermittent lockouts at start-up often point to a degraded cell rather than a control fault.