Defective CO/GAS Detector Help

Those things do go off for carbon monoxide and propane, as well as for methane and hydrogen sulfide (both components of animal flatulence). Our black lab sometimes sleeps right next to it, and when she does, it goes off once in a while. If yours was just replaced last year, it shouldn't be too old yet, but after you've confirmed that there's no gas leak or incomplete combustion which could threaten your life, consider the pet question.