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120VAC Hardwired Smoke Alarm with Battery Backup

  • 120VAC Hardwired Smoke Alarm with Battery Backup
  • 120VAC Hardwired Smoke Alarm with Battery Backup
  • 120VAC Hardwired Smoke Alarm with Battery Backup
  • 120VAC Hardwired Smoke Alarm with Battery Backup
  • 120VAC Hardwired Smoke Alarm with Battery Backup
First Alert Smoke Alarm SA9120BCN

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120VAC Hardwired Smoke Alarm with Battery Backup

The First Alert 120VAC Hardwired Smoke Alarm with Battery Backup works exceptionally well in detecting flaming fires. Capable of wiring directly into your home's electrical system, these alarms feature a near effortless installation process. This alarm comes equipped with a Mute Button that serves the dual purpose of quickly silencing your alarm as well as testing its function.

First Alert's series of 120VAC Hardwired Smoke Alarms with Battery Backups also come equipped with an EZ access battery door that removes the hassle and burden of collecting your alarm from the ceiling and replacing its batteries. The combination of a Battery Backup that provides optimal protection in the event of a power outage and an increased emphasis on the unit's 85d output establish the ultimate in peace of mind. This alarm comes with a 10 year limited warranty and complies with UL217 Standards. Save additionally with the purchase of this bundle.

This alarm is also capable of interconnecting with up to 12 other First Alert or BRK hardwired alarms.

This smoke & fire alarm is for you if:

  • You want alarms wired directly into your home's electrical system with the added safety of a battery backup.
  • You want to easily mute unwanted alarms with the press of a button.

Where To Place Safety Smoke Alarms:

  • One in every bedroom, and at least one on every level of the home.

Recommended replacement for the following obsolete models:
BRK 4120B
BRK 4120SB
First Alert SA4120B
First Alert SA4121B
First Alert SA4919B

120VAC Hardwired Smoke Alarm with Battery Backup Features:

  • 120vac hardwired, easily replace existing or install new hardwired alarms into home's electrical.
  • Battery backup, provides consistent protection for added safety during power outages.
  • Mute button, mutes unnecessary alarms. also tests alarm functions with same button.
  • EZ access battery drawer, no need to remove alarm from ceiling to change battery.
  • Optional theft-prevention lock, when activated, batteries and/or alarm cannot be removed without proper tool.
  • Ionization smoke sensor, optimal smoke detection from flaming fires.
  • 9v battery included.
  • Loud 85db alarm.
  • 10-year limited warranty (does not cover battery), smoke alarms should be replaced every 10 years for maximum protection.
  • Meets UL217 standard.
  • Emits T3 Pattern.
Click Here to Write a Review for this Product. Review

Average Customer Rating Based on 177 reviews: Rating: 4.94915254237288/5Rating: 4.94915254237288/5Rating: 4.94915254237288/5Rating: 4.94915254237288/5Rating: 4.94915254237288/5

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 Great service - 01/10/2018
Reviewer: jackie floen
No problem with orders, received exactly what I ordered, prompt delivery.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 - 01/10/2018
Reviewer: Kathy Romano
Easily replaced our existing alarms that are no longer working with these.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 - 12/26/2017
Reviewer: JoAnn Landry
Easy installation.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 - 12/26/2017
Reviewer: Ian Montgomery
Replaced a 8 year old unit, fit and worked as expected. Glad they still make this model. Would have been a pain to install another style.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 Low price, high quality and easy to install - 12/25/2017
Reviewer: Gangqing Hu
The price for the three sets of 120VAC hardwire alarm I ordered from First Alert beats anywhere else. The shipping was fast and the installation was easy and straightforwards as the model is compatibile with the ones to be replaced in my house.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 really good product - 12/19/2017
Reviewer: Eileen Trainer
completely satisfied. Thank you.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 Easy - 11/07/2017
Reviewer: Raymond Dunleavy
Dealing with the first alert store was great. Order came on time and people I dealt with were VERY HELPFUL. Smoke alarm was a replacement from an old one. Matter of changing electrical cable and plugging in. Easy

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 120VAC Hardwired Smoke Alarm with Battery Backup - 10/24/2017
Reviewer: Charyce Hill
I have 12 of this smoke alarm in my home, all of which have been perfect for the past 12 years. Had to replace only one unit as a plastic clip that holds the battery in place broke. Highly recommended.

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 - 10/04/2017
Reviewer: donald kreindler
swapped out older alarms and it was seamless

Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5Rating: 5/5 - 09/20/2017
Reviewer: donald kreindler
Very happy with this product. I used it to replace an existing one and it just slipped right into place.

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Q: What is the proper placement of smoke alarms?
A: It is important that you have the proper placement for your smoke alarms. Install your alarms at least 20 feet from appliances like furnaces and ovens, which produce combustion particles. Alarms should be at least 10 feet from high humidity areas like showers and laundry rooms, and at least 3 feet from heat/AC vents. Be sure to install a smoke alarm in each bedroom, one at the top of each stairwell, and one on every level.

Q: My smoke alarm keeps chirping and beeping. Why does my smoke alarm chirp intermittently?
A: It is likely that the reason your smoke alarm keeps chirping and beeping is that the battery is low. Whenever your smoke alarm keeps chirping, replace the battery immediately.

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.

Q: Why doesn't my smoke alarm sound when I push the test button?
A: It is important that you frequently test your smoke alarms. When you are testing your smoke alarm, there are a number of reasons why the alarm might not sound:
  • You may not be holding the test button down long enough. Try holding it down for up to 10 seconds (20 seconds on photoelectric models) .
  • Your battery may not be installed properly or snapped all the way in place. Even if the alarm sounded briefly when the battery touched the terminals, you still need to make sure it is snapped securely in place. If the battery is loose, in cannot power the smoke alarm properly. After installing new batteries, be sure to test your smoke detector.
  • Your AC power may not be on. AC and AC/DC units will have a power indicator light (red or green) that shines continuously when they are receiving electrical power.
  • If you have a 10-Year model, the smoke alarm may not have been properly activated. If the tab broke away before the alarm was activated, you can use a toothpick to move the switch over to test the alarm.

Q: Why does my smoke alarm go off when I install a battery or turn on the AC power?
A: It is normal for smoke alarms to go off and sound briefly (up to 5-10 seconds) when you install a new battery or when they are powered up. If the alarm continues to go off and no smoke is present, the cause may be one of the following:
  • There may be insufficient battery power, try new batteries.
  • Problems with voltage or insufficient electrical power (brown out) may cause a continuous weak sounding alarm. For AC or AC/DC models, temporarily disconnect power at the service panel until the brown out is over. If you do not restore the AC power, your smoke alarms cannot warn you of a fire.
  • Incompatible warning device. If an incompatible alarm or auxiliary device is linked into a series of AC or AC/DC smoke alarms it may cause the system inadvertently go off.

Q: My smoke alarm keeps chirping, even with a new battery. What is causing this?
A: There are a number of possible causes for your smoke alarm to keep chirping even with a new battery.
  • It is possible that your smoke alarm "silence" button was pushed by mistake. The alarm will now "chirp" once a minute for up to 15 minutes before resetting.
  • Are you sure it's the smoke alarm? Funny to ask, but other devices have similar low battery chirps or warning tones.
  • Your "new" batteries may not be fresh. If batteries are stored, especially in cold areas like refrigerators, they lose their charge more quickly. Always check the freshness date on the package when buying new batteries. Keep plenty of replacement batteries on hand so that you are sure to always be protected by your smoke alarms.

Q: I lost my First Alert smoke alarm owner's manual. How can I get a new one?
A: First Alert smoke alarm owner's manuals are available online for download at no cost. Find your alarm in our Smoke Alarms section.

Q: Why does the National Fire Protection Association (NFPA) recommend that home smoke alarms be replaced after 10 years?
A: Smoke alarms have a limited life. Although each smoke alarm and all of its parts have passed many stringent tests and are designed to be as reliable as possible, any of these parts could fail over time. Therefore, you must test the devices weekly. The unit should be replaced immediately if it is not operating properly. The performance of smoke alarms older than 10 years is simply not reliable. To ensure your family's safety, all carbon monoxide and smoke/CO combination alarms need to be replaced every 5-7 years. All smoke alarms need to be replaced every 10 years.

If it's time to replace your alarms, consider the NEW 10-Year Life series and never have to worry about a battery replacement for the life of the alarm.10-Year alarms are available in smoke,carbon monoxide and combination alarms.

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