System Sensor released a new white paper that explains when and why system-connected carbon monoxide (CO) detectors need to be replaced. A complimentary copy of the document, “Eliminating Confusion: The Limited Life of Carbon Monoxide Detectors,” may be downloaded from Because the CO gas sensor within a detector has a finite life span, the entire CO detector must be replaced when the sensor reaches its end of life (EOL) in compliance with UL regulations. All system-connected CO detectors have a limited-life gas sensor. However, not all of them have the capability to send the gas sensor’s EOL signal to the control panel. “We wrote this paper because we wanted to emphasize the difference between system-connected CO detectors and system-connected smoke detectors,” said Richard Roberts, senior product manager for the System Sensor Security Business Unit. “We wanted to get the word out so that expired CO detectors get replaced.”