Had the same problem with ours in our 2005 PW Excel when it was brand new. Phil at PW sent me a new replacement which I changed. The next trip, in the middle of the night, it went off and I thought I was going to have a heart attack! No, there was no gas leak, we don't have a dog and no beans for dinner! Oh and the wife uses hair spray in the morning only.
After some research and tinkering, I located an adjusting screw and and "toned" things down so that it works fine now after some testing. But, I still have not reattached the stupid thing because I don't think my heart nor my wife's can take the jarring shock in the middle of the night when I'm deep asleep! Yup, I'll take my chances!