The alarm is also sensitive to various aerosols, so be sure to check out what you have stored in the bathroom cabinet. Anything giving off an odor, or otherwise vaporizing that may be odorless, would be suspect. Hairsprays, bug repellents, deoderants, etc.
I had this problem a few years ago, but it turned out to be a piece of fiberglass insulation that had fallen in the combustion chamber of the fridge, which presumably resulted in the production of CO.
http://www.trailmanorowners.com/foru...ad.php?t=11945
As a side note, as mentioned in that thread, CO detectors that TM installs (or at least used to) have a 10-year (or less) life, after which its effectiveness apparently diminishes. I replaced mine, and the new one only has a 5-year life. In any event, cheap insurance.
Drop-in replacement:
http://www.trailmanorowners.com/foru...ad.php?t=10507
Dave