What is the Constant Yellow Light on the Smoke and/or CO Detector?
Updated
The Smoke Detector, Carbon Monoxide Detector, and 2-in-1 Smoke & CO Detector all feature a Tamper Switch, to make sure that the device is properly secured into its mounting bracket.
It’s a small button on the back of the unit that is normally held down by part of the mounting bracket. When it is not held down properly, you will get a warning signal:
Smoke Detector: Solid yellow, chirps every minute
Carbon Monoxide Detector: Solid yellow, chirps every minute
Smoke & CO Detector: Yellow light flashes every 4 seconds, chirps every minute
When placing your Smoke Detector, CO Detector, or Smoke & CO Detector, back into its mounting bracket, make sure to twist it fully until you hear it snap into place. The yellow light warning should stop immediately.
If you still see that yellow light, it is possible that the mounting bracket itself may be screwed into your wall or ceiling, causing the plastic to warp slightly. It may help to unmount the unit and slightly loosen the screws. Then try mounting the detector again.