Kidde Firex KF20 Optical Smoke Alarm - Mains Operated with Battery Back Up

Good quality and easy to install.

Quite a nice neat and tidy unit with a green light that glows constantly to indicate that it is powered on and a red light that flashes every few minutes to indicate that it’s functioning properly. I bought this to replace an old smoke alarm that had malfunctioned after many years. I was fortunate to be able to connect to the existing junction box above the ceiling where the old one was connected. Probably not so straightforward if you’ve got to start from scratch.

Exact replacement for old alarm

I had two of these. I installed them a couple of years ago. A few nights ago, the one on the upstairs landing decided to set itself, and the linked one downstairs off at 4 in the morning (why do false alarms always happen when you're asleep?) I could not get the thing to reset so I ended up ripping it off the ceiling mount breaking the mount in the process. Since the one downstairs still seemed to be working fine, I ended up buying the same make and model as a replacement. The old mounting box wasn't a Kidde box. The new one is. I did find the new Kidde box more difficult to fit than the old one and the alarm more difficult to fit in the mounting box (there is significantly less room for wires).

I did my research so I could use the base plate and electric plug of the old one (a Firex 4973) and avoid the cost of an electrician and still be safe to DIY this job. The KF20 is that kind of simple to install replacement. I only needed ladder, a flathead screwdriver to push the little button in and turn the whole front cover anti-clockwise. Then I just gently (with a little nudge under the clip ) the plug off and voila... ready to receive the new one. The new one had a long yellow strip of plastic over the enclosed battery that needed to be removed when installing to get the battery to operate, but confusingly on the strip in small lettering it stated "permanently connect ac power before removing - which is impossible to do as the battery cover is held down by the plug when it is inserted. So I did a quick call to their technical department and the gentleman said "no go ahead remove it before installing the plug bit. No problem but we only write this on there because sometimes people remove this plastic strip and then wait weeks before installing the whole thing and without it being plugged into the mains the battery drains whilst it is laying around. Ok, once I knew that I pulled the strip, heard the loud beep of contact, sign the battery is working . Then got on the ladder attached the 3 pin plug, folded the wiring neatly and twisted clockwise the cover onto the base, nice little click ... And all done and dusted. I have gone and ordered a new one for upstairs too ( that was a ionised one, but they have been phased out ), but I checked and base plate for that one (he said on the phone) fits as well with this model too and so does the plug. Lets hope that one goes as smooth as this one : less that 10 minutes, including the call. Even a 59 yr old woman can do this installation, lol! Love how this brand keeps it simple and really customer friendly with same base plate and plugs.... some mobile phone companies could learn a thing of 2 from these guys : )

Exactly same as the old ones easy to fit no hassle

Very easy to install, worked a treat for what I required.

Good buy