Question:
I'm trying to temporarily remove an ESL hard-wired smoke detector from the ceiling, but I don't know what is holding the darn thing up there. I don't see any screws, and don't want to break anything by forcing it off. I tried turning the main compartment while holding the base and it doesn't budge. What's the proper way to remove this thing without breaking anything?

Answer: Call the alarm company first if it's monitored! Assuming it's a model 449 .. There is a small vertical slit on the side of the unit. Push a trim screwdriver in the slit and the cover will hinge downwards. This will give you access to the mounting screws. It's easier to separate the terminal block from the unit, then to unhook the wiring. (you'll see what I mean)