This particular unit was installed in March 2016, and so I would doubt (and hope) that age has not been to blame.
As it turns out, someone was spending the night in our TM when the alarm went off, and upon further interrogation (
), I learned that they had just used the bathroom just prior to the alarm going off, and then went to the kitchen sink where they used some hand sanitizer (which are nearly all universally ethanol, as this one was). So, my theory was that, in this instance, that's what set it off.
Dave