I need to change battery for my home smoke detector, but I have no idea how to open this model.
I found many video tutorial on google, but have not seen any model similar to this one.
Does anyone have experience on this model?
HEMS, the vendor, answered my enquiry.
There is actually a clip (first image in the original question) with an arrow mark on it. The problem is that the mark is uncoloured, very difficult to be noticed from where I stand.
Push the clip to the left to release the lock, then pull down the whole thing.
You will find the latch hardly slides: it has to move about 1mm and then pull it down gently because the hook has a habit of snapping off.
Try simply grasping the lower portion of the detector unit and then try to turn it left or right. It may turn a short distance and then simply pull straight down.
AC Powered smoke detectors like this almost always have a plastic receiver piece that screws to the ceiling / electrical box. The AC power wires attach to a short harness and connector assembly that passes through a hole on the receiver plate. This connector then attaches to the top side of the detector unit. At installation the detector unit has fingers that match up with slots in the receiver plate. Then unit is simply pushed up into place and then rotated 25 - 35 degrees to lock it into place on the receiver piece.
My suggested removal procedure is the reverse of this common installation procedure.