It turned out that somewhere during the course of the day, my husband accidentally hit the reset switch and shut down the system. Just before I went to bed I noticed the light was no longer blinking. Thought that was strange so read up on it, and determined that was likely the culprit. Seeing as I was already dressed for bed and there was a thunderstorm going on outside, I wasn't about to test my theory by turning the propane tank back on. I did however, make a point of waking my husband to tell him I'd solved the problem, and he could fix it in the morning. In my own defense, in 6 RV units, this is the first one that's actually had an LP decector.