Ultraviolet intensity sensor for Trojan disinfection systems, 30-degree type, with an output scaling of 20 mA corresponding to 100 W. A UV intensity sensor reads the germicidal output actually reaching the water at 254 nm, which is the only direct evidence that the reactor is still delivering its validated dose. Lamp output falls with age and quartz sleeves foul, and both show up here before they show up anywhere else, so the controller alarms on this reading rather than on lamp hours alone. Trojan intensity sensors of the same physical form are not interchangeable across different view angles and output scalings, so match the markings on the sensor being replaced rather than the shape of its body. The 30-degree and 40-degree sensors are different parts and are not substitutes for one another. A 30-degree sensor supplied complete with a 1 metre cable is stocked as a separate line; this one is the sensor on its own. Contact us if you are unsure whether this part fits your UV system.