- About The Store
- Home Safety FAQs
View Cart 0
To be notified when this item is back In Stock, please enter your Email Address below:
The First Alert Hardwired Dual Photoelectric and Ionization Sensor Smoke Alarm with Battery Backup is designed to provide peace of mind. The photoelectric and ionization sensors on this fire detector alert you to both smoldering and fast-flaming fires, offering comprehensive detection and early warning. The 85-decibel fire alarm can connect to other compatible hardwired detectors for larger spaces.
Dual Sensors Detect Two Kinds of Fire
The First Alert Dual Sensor Smoke Alarm features photoelectric and ionization sensors for increased detection. The photoelectric sensor detects smoldering fires from objects like cigarettes burning on furniture or in trash cans, while the ionization sensor detects fast-flaming fires like erupting kitchen grease fires or combustibles. The dual sensors on this fire detector provide you and your family with the earliest warning possible.
Designed for Fewer False Alarms
Smoke from cooking or even shower steam can sometimes set off a smoke alarm. The photoelectric sensor on the First Alert Dual Sensor Smoke Alarm is sensitive to smoldering fires while reducing false alarms. The photoelectric sensor is smart enough to distinguish real threats from everyday activities, resulting in fewer annoying false alarms.
Battery Backup for Detection in a Power Outage
The fire detector is hardwired, but it also features a battery backup to help ensure the smoke alarm can still function in the event of a power outage. The unit requires two AA batteries, and comes with a low-power indicator to alert you when they need to be replaced. A one-touch silence/test button makes it easy to test the detector monthly or silence it during a false alarm.
Optipath 360° and Interconnectivity for Larger Spaces
The First Alert Dual Sensor Smoke Alarm easily connects to other compatible hardwired alarms, making it the perfect solution for larger buildings such as institutions, dormitories, hotels and other multi-family dwellings that use single station smoke detectors. The smoke and fire detector includes patented Optipath 360° technology that provides 360° of access to the alarm, and its 85-decibel siren is designed to be loud enough to awaken even the soundest of sleepers.
First Alert Hardwired Photoelectric and Ionization Smoke Alarm 3120B
In this guide, we'll be showing you how to install First Alert Hardwired Smoke and Carbon Monoxide Alarms. Here are a few items you'll need before starting the installation process: Needle-nose pliers or utility knife, screwdriver, wire stripper, wire nuts and a ladder.
Hardwired Smoke or Carbon Monoxide Alarm Requirements:
To begin, turn off power at the junction box and connect your alarm to the building's electrical wiring.
|Attach to black wire on power connector|
|Attach to white wire on power connector|
Standalone (single-station) alarm: This wire is not needed; tuck the orange wire into the junction box.
If you are installing more smoke or carbon monoxide alarms, you'll want to repeat the process throughout the building. Interconnected smoke and co alarms must meet all requirements:
The same fuse or circuit breaker must power all interconnected alarms.
Up to 18 compatible detectors can interconnect, with a limit of 12 smoke alarms.
The total length of wire interconnecting the alarms should be less than 1,000 ft. (300 meters). This type of wire is commonly available at hardware and electrical supply stores.
All wiring must conform to all local electrical codes and NFPA 70 (NEC). Refer to NFPA 72, NFPA 101, and your local building code for more information.
Interconnect wiring diagram:
If you have any doubts or reservations about these interconnect requirements, please contact an experienced electrician to install your wiring and hardwired alarms.
Once you've installed your hardwired alarms, you'll want to restore power to the junction box. Under regular operation, the power indicator light on the alarm will shine/blink to indicate that it is receiving AC power.
Here's how you can test standalone or interconnected alarms:
Standalone Alarms: Press and hold the Test/Silence button until the unit triggers an alarm.
Interconnected Alarms: Press and hold the Test/Silence button until the first unit triggers an alarm. All interconnected detectors should sound off. Repeat this process to test each alarm in the interconnected series.
Other reasons include: It could be a different device or appliance such as a security system, monitor, carbon monoxide alarm, or other device which has a similar low battery or alert signal. Some of the same factors that cause unwanted alarms can cause intermittent alarms: dust and insects in the alarm or power interruptions in hardwired alarms. Improper wiring on AC or AC/DC smoke alarms. AC alarms will chirp every 5 seconds if the interconnect wire is grounded. The orange interconnect wire should NEVER be grounded; it should only be used to interconnect other smoke alarms or compatible devices.
Average score based on 29 reviews
- Reviewed: 10/26/2022 by Isabel M T
Easy To Install
Installed all 4 of them and interconnected them, one in each bedroom and the basement.
- Reviewed: 12/28/2020 by Miguel Henry
I purchased this model because of the dual smoke detection features plus the carbon monoxide and I am happy so far with the product.
- Reviewed: 07/01/2020 by Massimo Ferraris
- Reviewed: 09/11/2019 by Philip Davis
Desired item delivered correctly as expected. Easy to install
- Reviewed: 04/20/2019 by Neil Fitzpatrick
I received three smoke alarms. Two for replacement and one for a new installation. I have not installed them yet.
- Reviewed: 01/26/2019 by Joseph Cudzynowski
Worked well during a recent furnace meltdown.
- Reviewed: 12/03/2018 by Anne L Haun Rymski
wired in dual smoke alarm
Son-in-law had no difficulty with installation. No false alarms which was major problem with original from another company to point it had to be disconnected.
- Reviewed: 09/20/2018 by Michael Wentink
First Alert Great products
I have just recently replaced all my smoke detectors throughout our 10 room B&B. I bought all First Alert units and particularly like the 2 AA battery design rather than the 9 volt. The batteries are much cheaper. I also later bought three wireless for each floor to improve fire alter status.
- Reviewed: 05/28/2018 by Bonnie Scherer
Item received in good shape. Easy to install. Good instructions. Product works great.
- Reviewed: 11/09/2022 by michael b
easy to install especially if you already have the newer bases installed-also like the AA cells replacing the older 9 volt