Ashok, I too have this very problem. My years old Almond+ randomly shuts itself off. Because I have another router for my ethernet connection to the Internet, I don't realize that the Almond+ has once again shut itself off, until one of my scripted automation routines does not execute. When that happens, I have learned over the last several months to always go check the Almond+ first and, sure enough, I always find that it has shut off. Now, I don't even have to go to the room where it is located, I just try to access it via my desktop computer, which will be unsuccessful because it has shut itself off.
It has the latest software update (AP2-R090-L009-W016-ZW016-ZB005, as of this moment).
I always have to pull the power plug to hard boot it, and then it always returns to "normal"—for a while. Eventually, it will shut off again, sometimes within hours, usually, days, and once it was good for a couple of months.
It has happened three times in the last 2 days. I just reset the screen timeout to 60 seconds (it had been at 3600) thinking this might help keep it cooler, and after waiting for the screen to shut off, I placed the unit face done on a cold granite countertop for the same reason. If this does not work, unless you have some other suggestions, I will have to assume that the unit was defective out of the box.
I will be eagerly awaiting your reply.
Thanks.