How to Install Hard Wired Smoke Detector - Easy Installation First Alert Smoke Detector Model 9120B 

Great video-really appreciated the step by step to switch out the First Alert detector, especially the detail on connecting the wires at the end. We ended up making several trips up/downstairs to get all the tools we needed: extension cord to plug in a light, 2 different screwdrivers & plyers -couldn't get the caps off the original wiring. Don't think we could have handled this without your video! Thanks!

I suggest looking at a video showing the RIGHT way to connect wire nuts if you need to do that step. Also, the video does not explain how the red wire is used, and why it has a cap on it. HINT: When used, the red wires allow all the smoke detectors in the house to communicate with each other in the event any alarm goes off.

Thank you so much for this video! I'll be trying to replace and rewire 6 of these this week. I'll come back to let you know how I do :)

Thank you!!! I needed exactly this video - especially the end with the rewiring part! Really appreciate this!

Thank you for your video. Watched a few wasn’t helpful, but yours was right on point. 👌🏽😅

THANK YOU!! Best Video on this smoke detector!! I've watch 3 other videos and the other ones, Ignored the Orange wire. A++

Thanks for the schooling. I didn't know they come with adaptors, great!

The battery set up for this alarm is c*** pure c***

uh, yeah...that little cap on the ORANGE wire does not just pull off like it does in the video. I had to cut it off,,,,PIA

If you like me bought the dual package with the 2 in 1 CO alarm also, the adaptor is only packaged with one side of the alarm, so make sure you unpackaged both frustration packages and the adapters are on the left alarm side. I almost thought I don't have that adaptor at all. Also, mine has a 9V battery back up with a battery door locked as "DEFAULT" and was taped behind the factory label and a transparent film blocking the connection. It instructed to pull the transparent film off before use, but it's stuck in there so hard that you have to UNLOCK the stupid battery lock, open up the battery door and still struggle to pull that piece of transparent plastic out. What a stupid design and instructions. They should have highlighted that the door lock is LOCKED by default. Anyways.

Grate video, God bless you sir

Hey thanks! Great video.

Thank you. I follow your video.

The orange wire tip did not slip off. I had to clip it off.

How do you remove the mounting bracket?? It doe snot just come off like in the video!

Smoke alarms (depending on the type) last 10 years. Not seven