USI Electric MICN109 Hardwired 3-in-1 Smoke, Carbon Monoxide and Natural Gas Alarm

I replaced a hard-wired-with-battery-backup smoke alarm by USI with this 3-function smoke, carbon monoxide and natural gas alarm. I used to have to replace the battery in the smoke alarm each year. This alarm is also hard-wired like the previous one, but it seems one does not put in a battery. It seems that it has a 10-year battery pre-installed. (It seems a bit hard to believe.) I guess after 10 years one needs to replace the whole item. Thus far I have not had any false alarms. It was easy to install because the previous alarm (smoke alarm only) was the same brand.

The product was a replacement for an old USI smoke detector. We decided to replace the smoke detector with the 3 in 1 for additional safety. I purchased the the above unit in September 2022, went ahead and installed the unit despite the manufacture date of Feb 2015. Like others have stated, this unit sat on a shelf for over 7 years. The unit worked great until a week and a half ago. The carbon monoxide detector starting going off about 10 PM. We immediately placed a carbon monoxide detector from another floor in the same area, that detector had a 0 reading, meaning no carbon monoxide was detected. Which makes sense as we live in the south, where it is currently very hot, and we don’t have a gas furnace running, nor any vehicle or any other gas appliance. We tried changing the battery, that did not help. I went to the store and purchased another carbon monoxide detector for $60.00, it too showed a zero reading. We finally had to disconnect the hardwire and remove the unit so that we could get some sleep, along with our terrified dogs. As per USI, this unit has a 7 year warranty. I called and left a message with all the pertinent t information…I’m still waiting for a return call. It’s absurd that the unit worked for less than 1 year! I do not recommend this product.

All my smoke detectors were past their 10 year life, so I bought two of the USI MICN109 Hardwired Smoke/CO2/Gas detectors for hallway/basement... and two regular smoke detectors for my bedrooms. After shutting off the power and checking with a non-contact tester...I changed the pigtails...I would recommend stripping another 1/4" off the wires, as it will make wrapping the stranded wire around the solid house wire better contact when you add the wire nuts. Once I changed the base plate I pulled the battery tab and mounted the units. Once the power was restored...all unit synced and are working well. Update...one of the units malfunctioned after 1 year. I called the Company and they replaced it within a week. The new one is working great!

I purchased these combo detectors to replace the USI-7795 that my house came with when built in 2009, The 7795 started giving us fits and false alarms in about 2013, and after calls to USI for help troubleshooting I gave up and just removed them from the ceiling leaving the ugly wire e harness hanging down. (I still had 5 USI-1204 smoke detectors in use) All the detectors were wired together so I wasn't sure what type of compatibility issues I might run into if I tried to mix and match brands, I knew i didn't want to buy more USI-7795s. So nothing happened for 3 years which is sad. Move up to December 2016, and the USI-1204 smoke detectors started with false alarms. I admit I have been doing some light remodeling in the house that involved some sanding. I never thought to cover the detectors. Also after some research, I was reminded that these type of detectors do have a short life span. I assumed since they were warranted for 5 years, the expected lif must be close and mine were 7 years old with lots of extra dust. I checked the USI website, and the 7795 had been discontinued and replaced by the MICN109, which also offered a natural gas detection. The website said the MICN109 would fit on the base of the 7795 which were still in place. I also ordered 5 new 1204 smoke detectors directly from USI, but amazon was the best price on these. The good news is when I installed them, the wiring harness did match but the base did have to be changed to the new one that came with it. Better the base with 2 screws than turning off the power and re-wiring. So far, so good. It is hard to give a product a 5 star when you don' even know how well it's actually going to do it's job, until there is an emergency. The price was good, the seller shipped fast. Hopefully this helps someone who has trouble with the 7795.

I purchased five of these detectors to replace the out-of-date detectors which my home inspector failed to discover. They are easy to install. They matched up perfectly with the outlets. These detectors are designed to be linked to each other so in the event that one detector goes off, they all go off. Detectors have a limited life (seven years is typical), so please ensure yours are still good. The expiration date is stamped on inside the housing. I placed a label on the outside cover so no one will be tricked in the future. My long standing habit is to replace the 9V backup battery each year on federal tax day. Everyone pays taxes so it's an easy date to remember.