A couple of years ago I had two ten year smoke alarms provided by one of those help the elderly to stay safe schemes. This week-end one of my alarms stared to blast out its warning. I checked my house including the loft only to find nothing amiss. Following the instructions I tried to switch it off. Nothing doing. After awhile I did manage to stop it blasting my eardrums only for it to start again about two hours later. I’m not daft, I thought “I’ll take out the battery”. With this design the battery cannot be disconnected. After several removals of other key parts the thing is still apparently alive. We decided that a replacement was needed and one was duly purchased. I disposed of the old one in the rubbish bin outside. Late evening I saw a couple of my neighbours walking up and down our road trying to find the source of the alarm which had started up again. Removing the offending object from the bin I decided that if a scientific approach to removing the key bits was not working a more practical approach was required so I hit it with a brick. These things are virtually indestructible because even that failed to stop it. Silence eventually prevailed until about 11oclock this morning when, wail, wail, wail, it started again. This time however it is well and truly silenced. I have dismantled all the electronics.
I wonder how many other units of this model have failed in the same way?