Customer Reviews

First Alert SC9120B Hardwire Combination Smoke/Carbon Monoxide Alarm with Battery Backup

5 star:		(44)
4 star:		(13)
3 star:		(3)
2 star:		(2)
1 star:		(15)

 

 

Our house was wired for smoke detectors -- specifically the rather cheesy BRK 4120SB, which delights in false "low power" chirping. My goal was to replace the ones in the bedrooms with combination alarms that would alert us not only to smoke but to the presence of carbon monoxide. (Not to scare you but harm and even death from carbon monoxide poisoning are definite risks, especially in a home with deep-sleeping teenagers.)

I needed units that would be compatible with the wiring of our current system, and ideally ones that would accept the power leads, as wired. After some research here and elsewhere, I called the BRK help line and got definite information about the unit that would be compatible, as well as locations within the home where I both should and should not install units.

I ordered two units to start with, still being a bit leery of my previous experience, and can say that installation took less than 5 minutes per device.

1. Follow the instructions for removing the plastic tab in the battery door of your new unit and pushing the button to test your new unit. If all's well, proceed. Disregard the "locking pin" stuff unless you are in a shared dwelling and are concerned with someone walking off with your 9-volt battery. (This was the weirdest part of the instructions, frankly, and this is my guess on why it's there.) **Important: you are listening for 3 tones, pause, 3 tones, pause, 4 tones, pause, 4 tones. There is a typo at the bottom of page 3 of the instructions, so I've just verified with BRK that the tone pattern I'm mentioning is the correct one.

2. Twist off and unplug your current unit.

3. Back the two screws holding your collar to the ceiling so you have enough clearance to remove the collar.

4. Install the new collar.

5. Install your new unit. (A wired plug is included in case you need to swap your existing plug for the new plug.)

Fellow owners of the 4120SB will find that the upgraded unit sets and locks into place in the ceiling *much* easier and more reliably. Ditto with the battery door. Note that on the SC9120B, if you're having problems with the battery door not shutting (a) there is a little trigger tab that you should be able to push down with a fingernail and/or (b) hold the unit upside-down.

***A word, please, about longevity, since the primary purpose of an alarm is your safety.

1. Replace your batteries at least once a year.

2. Combo smoke/carbon monoxide units have a 5-year life span, per BRK staff. Regular smoke alarms have a 10-year lifespan. Not replacing them within these timespans is, in my opinion, the most dangerous kind of false economizing. (Note also that if you need help, the BRK customer service apparently has improved greatly since the experience of earlier reviewers of the product line. The call I made in June could not have been more thorough and professional, even to dealing with the phantom beeps of my 5-year-old alarms.)

3. Whether or not you buy this or any smoke alarm product, please do yourself and your family two favors. First, label the plug (hidden) side of your units with the install and replace dates. Second, change your batteries at least once a year.


BTW, I gave the unit a 4 rather than a 5 because while the battery door and twist-on/twist-off issues are less irritating than on the earlier generation, they still do exist.

I have a rental property and this year, the city's new regulation required installation of these detectors. One of the detectors malfunctioned and the terrified tenant called 911, who proceeded to do over 1000 dollars in property damage.

I subsequently found out that even the EPA has admitted that many of the CO detectors they tested were unreliable, and either went off at too low of a level or did not sound at dangerously high levels.

According to their website, the best way to keep the building's inhabitants safe is to have fuel-burning appliances properly installed and maintained by licensed professionals to make sure that the gases (including CO) are vented properly.



I ended up doing a lot of research related to CO as a result. I have the documentation from the Fire Department indicating the levels that they measured (WAY BELOW the low threshold on the detector) even near the detector.

I knew that a problem was unlikely since the heat wasn't even ON at the time.

Nevertheless, they broke into two apartments, destroying irreplaceable historic doors and frames. Even the fire chief told me that if I have a hard-wired smoke detector/CO detector combo, I should get it replaced as they have had false alarms with that type of detector. But as mentioned on the EPA website, and evidenced by many other reviews on Amazon etc, CO detection is apparently in it's infancy and I'm surprised that these detectors are even being sold, much less required by law.

Unfortunately, according to my lawyer, it's more trouble than it's worth to sue the city, so I had to suck up the CONSIDERABLE expenses myself. Not to mention my poor tenant, who was (unharmed of course) but anxious.

I am so ANGRY, but the only thing I can do apparently is to WARN other people about these alarms. If you have one in your house and there's a false alarm, that's one thing. But if a tenant has a false alarm, you are vulnerable in many different ways.

The WORST thing about this type of alarm is that if the CO part malfunctions, you've lost your smoke alarm as well. In addition, since it's installed high on the ceiling, if it false alarms, you have to get on a ladder to turn the thing off.


I would not recommend the first alert smoke/CO alarm to ANYONE.

Received three BRK SC9120B replacements after original units (4 years old) started a low battery chirp with new Duracell batteries. Spoke with BRK rep. about problem and they sent three new units with Duracell batteries. The units worked fine for about two weeks before all three started to chirp a low battery signal. In that time our other three BRK smoke only detectors that were installed 4 years ago started the same chirping sound. Again called BRK and they were going to send us three replacements for them. After the nightmare of having six four year old BRK products fail in a matter of three weeks and three brand new replacement units fail in two weeks. I would stay away from BRK! I have read elsewhere about an issue with BRK and Duracell so I was a bit surprised when the new units arrived with Duracell batteries in them.

I bought this product to replace a defective older BRK Smoke/CO alarm unit (can't remember the model #, maybe SC6120?) about a month ago. This model is the official replacement for my older unit. I was hoping to just be able to plug this into the existing BRK mount but it didn't fit. I had to remove the old mount and install the new mount plate that came with the product. Not a big deal but a little extra work. So far I haven't encountered any problems with the new unit.

It was a breeze to install. Tested the unit and it has a piecing audible alert. Battery can be easily replaced w/o removing the unit.

I bought 2 of these to replace 3-year old models from the same manufacturer, installed by the builder. After 3 days one began the "low battery" beep, as mentioned by other reviewers here. However the problem was not the unit, but the installation. The house wiring is heavy 14 gauge solid wire, with wire nuts connecting the stranded alarm wires to it. In tucking the wires back into the ceiling, one of the power leads pulled out of the wire nut, leaving the unit operating on battery power alone. It's not made for battery-only operation, so the battery is exhausted in a few days. After carefully reconnecting the wire, the unit functioned as expected.

I should note that the builder had trouble getting all 6 alarms working correctly, with 3 different brands/models installed when we moved into the house in 2005. Since then we've had 50% of them fail, ALWAYS in the dead of night. This seems to be about par for the course, as I've heard numerous accounts from friends and family that mirror my own. In searching for replacements, I've found that there are only 3 brands to choose from, and they seem to come from only 2 different companies. None of them seem to be made to last more than 5 years, and the warranties are essentially worthless.

This product immediately triggered a false alarm. There was no way to stop this unit from indicating a false smoke alram other than disconnecting it, and pulling the 9V battery from the unit.

My condo unit had this alarm installed when I moved it. It was located at least 25 feet from the kitchen, around a corner and down a hallway, where there is plenty of air circulation. But it was so overly sensitive that it would go off nearly every time I used the cooktop. Never mind that nothing was smoking. It would even go off when I used the oven to bake a cake, for god's sake! When it went off while I was gently sauteeing mushrooms, on the back burner with the vent fan already on, I had had enough. In an apartment with no proximity to a furnace or a kerosene heater, I am not concerned about CO. And if every time I cook I have to open every window in the place and put the vent fan on full blast, I'll do without. An alarm that goes off all the time is as bad, or worse, than no alarm at all. I pulled it out and removed the battery.

Just failed an inspection by the fire chief because these detectors do not make a voice announcement explaining the source of the alarm. Quoting from the Massachusetts requirements for combination detectors:
"Acceptable combination smoke detectors and carbon monoxide alarms must have simulated voice and tone alarms that clearly distinguish between the two types of emergencies."

3 vs 4 beeps is not considered a clear distinction.
Do not get these detectors if you need to be up to code. On top of all this hassle, my return window expired and I sank $150 into 4 of these detectors that I can now throw away. The model that complies with Mass code is SC7010BV.

These BRK smoke alarms have issued alarms twice now, which lasted several hours each and resulted in lost work time. Initially, two of these would beep every minute and nothing I tried would stop it, so I had them replaced, and then these seemed to be OK, but almost every night we would hear a 1 second alarm. Then 2 weeks later, the alarms went off steady and nothing we tried would silence or reset them. We even had the gas company come out to check the gas applicances for CO2, since 2 of the units also had the CO2 detectors built in, but everything checked out fine, so I just started unplugging the units until the alarms stopped. A few days later, the remaining 3 alarms that I still had connected started another false alarm and eventually stopped. I don't have time to put up with issues like this, and it can result in not even believing your smoke alarms, when it may be a real fire! I only purchased these because they were plug compatible with the First Alert, but I will have to rewire the plug and purchase a better quality brand.