Two possibilities that we have experienced - with three detectors close together, it is a little hard at times to know which one is going off.
1. On our RE3, the smoke detector is on the ceiling, and directly above the other two detectors. Once when we thought the carbon monoxide detector was going off, it turned out to just be the smoke detector signaling "low battery". It did take us a while to figure this one out, because of the prior bad experience mentioned in #2.
2. On a prior instance, our converter failed, and was overcharging the batteries. The batteries were 'out-gasing", and the sulfur gas was coming into the living area. The carbon monoxide alarm was going off "big-time", and the smell was terrible.
I assume you are not experiencing the "bad smells", so, could it be that you just need to replace he smoke detector battery?? That certainly would be the easy problem to fix!!
Good luck in finding the problem.
