Help! propane detector went off now what?

We bought our new Minnie Winnie from a local dealer in March this year. On our 2 camping trips the propane detector has gone off in the middle of the night for no apparent reason. The detector was built 7/18/13. My only remedy at the time was to remove the 1 amp fuse. I built a simple water filled U tube manometer to test for leaks. After turning on the propane bottle and turning it back off again thus bottling the gas pressure up in the trailer the reading on the manometer did not change after 3 hours. It read 11.5" water column. With a spray bottle with dish detergent and water I sprayed every pipe/tubing joint outside and inside the trailer for leaks. None found. I am 100% convinced that there is not a propane leak. My dealer ordered a new detector under warranty and it should be in this week.