An ultra-violet (UV) assembly for treating a fluid with UV light has ahousing. Amounting bracket defines a slot and a hollow. A UV source includes: a tab thattwist-locks in the slot； a connector that aligns with the hollow； and an RFIDtag. An RFIDantenna interacts with the RFID tag to emit a RFID tag position signal. A flowswitchsends a flow signal. The flow switch includes: a guide； a shaft slidablymounted to theguide； a disc on the shaft； a magnet coupled to the shaft； and a sensor forgenerating amagnet position signal. During no flow, a spring biases the shaft so that themagnet ispositioned to be detected by the sensor. During flow, the flow appliespressure to movethe disc and, in turn, the magnet moves to be positioned to not be detected bythe sensor.
