Having used this type/model of Carbon monoxide/smoke alarm for the past eight years with no problems, I naturally felt it appropriate to buy another of the same type. Big mistake! I had read a number of negative reviews on Amazon, but thought that these were just a few cases of bad luck. Either I was wrong or my luck is no better!
I set up the alarm within minutes of receiving it. I followed the instruction to fit the batteries provided in the prescribed order. Why this should matter I don't know. Anyway, to no avail. The alarm went off like a banshee the moment the batteries were fitted. I tried pressing the test button - which did nothing to stop the siren. I then removed and refitted the batteries with the same result. I tried this several times before giving up and printing off the returns authorisation. Fortunately, Amazon make the process relatively painless - the package arrived at lunchtime and was on its way back by 2pm!
It seems to me that Kidde are having problems with this model. Maybe they have changed the design, manufacturing process or parts supplier over the past eight years. Until there is a reduction in complaints to virtually nil, I shall not be buying this item again. I shall try other manufacturers who attract fewer complaints. My advice to anyone thinking of buying this model is to do likewise.