BRK 9120B Smoke Alarm, 120V Hardwired w/ Battery Backup
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About this Product
The BRK 9120B smoke alarm is a great choice when it comes to affordability. Redeigned from the ground up, BRK created the 9120B model to directly replace past models while greatly improving sensing technology, installation ability, and improved connectivety. All around, the BRK 9120B is the perfect smoke alarm if you are looking for affordability, function, and ease of use.
The BRK 9120B smoke alarm uses new smart sensing technology to reduce false alarms more efficiently and more accurately than ever before. The BRK 9120B is designed for sleeping rooms in your home, hospitals, hotels, motels, college dormatories and multi-family housing units. Complies with NFPA101, UL217, CSFM, NFPA72, HUD, FHA, and other agencies. Where AC/DC silent smoke alarms are required, this model will work perfectly.
The 9120B model has the ability to be interconnected within a circuit of alarms and other alert devices such as bells, whistles, repeaters, fans, or switches. You can connect up to 17 devices, of which 11 can be smoke alarms, and 6 can be alternate devices.
Integrated within the BRK 9120B smoke alarm is a 9V battery backup to make sure your smoke alarms do not loose operation when your power fails, providing addtional security.
This item is the DIRECT replacement for the discontinued BRK 4120B, 4120SB, 4919 and 86RAC.
Wiring harness and communication protocol is the same across models (i.e. a 4120B will talk to a 9120B). When replacing an older smoke detector, only the mounting bracket needs to be changed.
- 120 VAC; Interconnectable
- 9V Battery Included
- AC Power Indicator
- Alarm Indication
- Battery Activation Tab
- Battery Back-Up
- Battery Drawer Lock
- Easy Install Mounting Bracket
- Ionization Sensor
- Low Battery Warning "Chirp"
- Missing Battery Tab
- Mounting Bracket Lock
- Quick Plug-In Power Connector
- Swing-Open Battery Door
- 120V AC
- Alarm Dimensions: 5.6" dia x 2.0" H
- Audio Alarm: 85dB at 10 feet
- Humidity Range: 10 percent to 90 percent relative humidity (RH)
- Operating Current: .04 amps (standby/alarm)
- Operating Voltage: 120V AC 60Hz w/ 9V battery backup
- Temperature Range: 40 Degree F (4 Degree C) to 100 Degree F (38 Degree C)
- Weight: 7.8 oz (9120B)
i think it is really good
it is excellent, it can detected smoke fast, it really help to maintain protected from fire.
on 09-18-2011 by eli
Easy to Install but . . .
Great service and price from Westside. Got these to replace outdated contractor-installed alarms. These installed easily on existing mounting rings and electric pigtails connected right to existing connectors. But these alarms are susceptible to spiders getting inside and setting off false alarms, usually in the middle of the night. While the case protecting the ionization detector has slots to prevent bugs from having direct access, small spiders get in through the gap between the mounting ring and the alarm case and set off the alarms. With the alarms being interconnected, the middle of the night the spider-induced alarms' sounding is, well, alarming. Then it''s usually necessary to take down the alarm with the problem and shake it vigorously to get the spider out.
on 07-29-2011 by Kawasaki Biker
Difficult to replace battery
These were installed in a newly built house that we bought in 2007. The only problem I have is that inserting the battery is very difficult. Otherwise I would give it 5 stars for quality.
on 02-16-2011 by Florida gal
Replaced 3 BRK 86RAC smoke alarms with 3 new BRK 120V Hardwired 9120B models. They ARE a direct replacement for the old ones, same plug ins. Out of the box, put up new brackets, old screws aligned perfect, plugged in, and pulled the battery tag. Did all three in less than ten minutes. Also received on delivery date, could not have been more simple. Outstanding!!!!
on 12-31-2010 by RFH
mon a mi
bonjour. what is for us is different than the states. we find these and buy for to change our old one. thank you for this. Ciao
on 02-17-2010 by Georges
this is right
part of the problem was that no one knew that this would work. after we called westside they shipped these to us and we installed them. so far, no issues. I guess as far as smoke detectors go, their sort of cute. much better than the old yellow ones that we had up there. I'm not even sure if they make them anymore.
on 02-17-2010 by Jennifer
we have the old ones and now we have the new ones and this is what we need. PJ installed them in all the rooms and then came back to tell me and I was surprised. He installed them so quickly. I was on this website looking for the shower heads and i see that this is what looks like I have. I think that maybe this is the best one on the market because i don't like cheap things.
on 02-17-2010 by Mr. Patel
I wish that I had known these were here. This is exactly what I needed. The connector is the same and thats important
on 02-17-2010 by Sussie LImpkin
I recently purchased 8 of these units for my home. They installed in minutes and work great!
on 02-03-2010 by Howie
direct plug in replacment
Had to repalce all the smoke alarms in my 15 year old house. These are direct replacment for the older RK alarms. Just had to change out the plastice mounting rings and they plugged directly into the original plug, no wiring changes. The units will tell y9ou which alarm is causing the alarm. The older ones took troubleshooting to find the offending unit.
on 05-10-2009 by PeteExcellent rplacement better technology
Talk about easy installation!
I recently had to replace my old 4120B. It took me 15 minutes to get it wired up and in the ceiling. At this price I might as well replace them all since its so simple.
on 02-19-2009 by Ethan
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Questions & Answers
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What is the difference between the BRK 9120 and the 9120B smoke detectors?
The BRK 9120 is hardwired only, while the BRK 9120B is hardwired with a battery back up.
I have the BRK SC9120B. Will the BRK 9120B be an exact replacement? The remaining units in my house all still tested ok.
You are able to replace a BRK SC9120B with a BRK 9120B, but please keep in mind that the BRK SC9120B is a smoke and carbon monoxide detector while the BRK 9120B is just a smoke detector.
I am replacing the BRK 86RAC units (have 5 of them) because one occasionally just begins to sound for no obvious reason. Is there a direct replacement or will the BRK 9120B smoke alarm use the same plug-in connector?
The BRK 9120B is the direct replacement for the BRK 86RAC.Wiring harness and communication protocol is the same across all models. When replacing an older detector, only the mounting bracket needs to be changed.
I have an older model BRK 4120B smoke detector that is chirping. I purchased this house from the original owners but cannot find a replacement. Please help.
The BRK 9120B smoke alarm is the direct replacement for the BRK 4120B.Note: This item is the DIRECT replacement for the discontinued BRK 4120B, 4120SB, 4919 and 86RAC. Wiring harness and communication protocol is the same across all models (i.e. a 4120B will talk to a 9120B). When replacing an older detector, only the mounting bracket needs to be changed.
When should one replace a fire alarm unit. I have the old model 4120B for about 7 years
It is recommended that you replace your smoke alarms every 5-7 years, unless otherwise specified. The BRK 9120b has an extended warranty of 10 years.
can you still buy the brk 4120b smoke detectors
No, the BRK 4120B smoke alarms have been discontinued by the manufacturer, and they have released the 9120B as an direct replacement.
can the 9120b brk smoke detector plug directly into a brk 4120b to replace a faulty one?
Yes, the BRK 9120B is a direct replacement and will plug into existing connections, however, you may need to replace the mounting bracket with the new one supplied with the 9120B model for proper mounting.
I have model # 9120B smoke detector. What kind of batteries do I need to buy?
The BRK 9120B uses a 9V battery
BRK9120B units. Have 8 installed and have replaced batteries for three years. Now have one units chirps in middle of night. There is no smoke or reason for unit to chirp. Have replaced the battery three times (with new batteries). Is the unit defective?
On the top center of the Owner's Manual (click here for PDF), is an alarm and light indicator guide that will explain the nature of the alarm based on the chirps and light signals. This will tell you what is triggering the chirps.
This unit has a 10 year warranty, if defective, it would fall under manufacturer warranty (handled directly through the manufacturer)
i have a old model 2812TH alarm, I removed the alarm thinking it was no longer working when i pulled it down from the celing there were four wires connected to four of the ten screws on the back (it was hard wired to my home alarm system) the alarm sound off and i had to disconnect the home alarm to make it stop. I also for got which colored wires went to which screws. My question to you is can i up grade to a combo fire and carbon monoxide model and use with my current home alarm system?
After speaking with a representative at System Sensor, we do not currently have any direct replacements for your model that are available. The model 2812TH is manufacturered by System Sensor and is an older model of theirs. Due to varying functionality, sensor usage, and wiring requirements, we do not have any cross-referencable models that we can guarantee will work.
We recommend contacting the manufacturer of the smoke detector model and see if they have an upgraded version of your model available for you.
Customer Service: 1-(800)-736-7672
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