A Carbon Monoxide (CO) detector is a home device that can save your life, as it detects CO gas. CO gas is colorless, tasteless and odorless, and a detector is needed to test ppm (parts per million) and alert you to unsafe levels. Resetting your First Alert Carbon Monoxide detector may be necessary after it detects CO levels and the situation has been resolved.
Look at your detector. You will see two buttons if your detector has an LCD display. One is labeled "peak level," the other "test." If your detector is ceiling-mounted, it will only have one button.
Press "peak level" and "test" at the same time if your detector is the LCD display type, and keep these buttons held down until it beeps and the LCD shows "000." It is now reset.
Press and hold the button labeled "test/reset" for 5 seconds if your detector is ceiling-mounted.