4-in-1 alarm protects against fast-flaming fires, smoldering smoke, carbon monoxide and natural gas (or methane).
120-volt AC hardwired alarm with backup battery is suitable for houses, apartments and mobile homes.
Universal Sensing Technology responds 87-percent faster to slow smoldering fires and responds quickest to fast flaming fires.
Features a quick activation pull-tab and a front-loading battery drawer for replacement without removing the alarm from the bracket.
Comes with a 7 year limited warranty.
Revolutionary Universal Smoke Sensing Technology
The USI Electric MDSCN111 Hardwired Smart Alarm is a 4-in-1 device that provides quadruple the protection with a single installation. This 120-volt AC alarm protects against (4) deadly household threats: fast-flaming fires, smoldering smoke, carbon monoxide and natural gas (or methane). Perfect for new or replacement installations, the MDSCN111 alarm is suitable for houses, apartments and mobile homes. Universal Smoke Sensing Technology responds 87-percent faster to slow smoldering fires and responds quickest to fast-flaming fires. Auto sensitivity calibration provides superior nuisance alarm protection and creates consistency in alarm sensitivity.
This 4-in-1 alarm has additional automatic features including: a self-diagnostics check to ensure proper operation, a sensitivity adjustment for changes in temperature or humidity and an end-of-service life warning that sounds when it's time to replace the battery. The 9-volt alkaline battery (included) continues protection in the event of a power outage. This combination alarm features a front-loading battery drawer for replacing the battery without removing the detector from the bracket. Mount the bracket to any standard wiring junction box and use the large mounting base to cover imperfections in drywall. For maximum protection, install an alarm inside every bedroom, outside every sleeping area and on all levels of the dwelling. The USI Electric MDSCN111 Hardwired Universal Smoke Sensing Smart Alarm comes with a 7 year limited warranty.
Warranty: 7 year Limited Warranty
Alarm Power Source: 120 volt hardwired & 9 volt battery backup
Q: WHY DOES MY SMOKE ALARM 'CHIRP' APPROXIMATELY ONCE EVERY MINUTE?
A: The smoke alarm chirps to indicate a "low battery" condition, meaning the battery needs to be replaced. Battery powered smoke alarms will chirp a minimum of 30 days before the battery completely loses power.
AC powered smoke alarms with battery backup will chirp indefinitely assuming AC power is present; if battery power is low, or battery is removed; until a fresh battery is installed. Approved replacement batteries are listed on the back of each smoke alarm and in the user's manual.
Certain model smoke alarms with a silence button (designed to silence the alarm during a nuisance alarm) may chirp to indicate the smoke alarm is in the silence mode. The chirp will stop after approximately 8 minutes and the smoke alarm will return to its normal operation.
Q: WHAT LEVELS (PPM) OF CARBON MONOXIDE CAUSE AN ALARM?
A: Carbon monoxide alarms are designed to alarm before the average healthy adult feels symptoms. Since you cannot see or smell CO, never assume it's not present. Underwriters Laboratories Inc. Standard UL2034 requires residential CO alarms to sound when exposure times and exposure levels of CO in the chart below. CO alarm levels are measured in parts per million (ppm) of CO over time (in minutes). The UL2034 Required Alarm Points are:
If the Alarm is exposed to 400 ppm of CO, it must alarm between 4 and 15 minutes.
If the Alarm is exposed to 150 ppm of CO, it must alarm between 10 and 50 minutes.
If the Alarm is exposed to 70 ppm of CO, it must alarm between 60 and 240 minutes.
Q: IS CARBON MONOXIDE HEAVIER THAN AIR?
A: Carbon monoxide is not heavier than air. A carbon monoxide alarm should be installed in a location where the alarm will stay clean, and out of the way of children or pets. Refer to the user's manual for specific installation requirements.
Q: WHAT DOES IT MEAN WHEN THE RED LIGHT ON THE ALARM FLASHES APPROXIMATELY ONCE EVERY MINUTE?
A: The flashing red light gives a visual indication that the smoke detector is functioning properly. It also indicates a working battery is connected to the smoke alarm.
Q: WHERE SHOULD I INSTALL MY CARBON MONOXIDE ALARMS?
A: It is very important to install a carbon monoxide alarm outside each separate sleeping area, and for maximum protection, install one in every bedroom. Many states now require installation of a carbon monoxide alarm inside each bedroom. For added protection, placement of an additional carbon monoxide alarm at least 15-20 feet away from the furnace or fuel burning heat sources is recommended. Install carbon monoxide alarms a minimum of 10 feet from sources of humidity like bathrooms and showers. In multiple-story dwellings, install one carbon monoxide alarm on every level. If you have a basement, install a carbon monoxide alarm at the top of the basement stairs, and in each separate sleeping area.
Q: WHAT AREAS SHOULD I AVOID INSTALLATION OF A CARBON MONOXIDE ALARM?
A: Do not install carbon monoxide alarms in garages, kitchens, furnace rooms, or in any extremely dusty, dirty, humid, or greasy areas. Do not install alarms in direct sunlight, or areas subjected to temperature extremes. These areas include unconditioned crawl spaces, unfinished attics, un-insulated or poorly insulated ceilings, and porches. Carbon monoxide alarms should not be installed in outlets covered by curtains, heavy furniture or other obstructions. Do not install in turbulent air-near ceiling fans, heat vents, air conditioners, fresh air returns, or open windows. Blowing air may prevent carbon monoxide from reaching the CO sensors.
Q: WHAT DOES THE CONTINUOUS GREEN LIGHT ON MY SMOKE ALARM INDICATE?
A: When a green light is present on your smoke detector, it means that AC power is currently operating the alarm.
Q: THE GREEN LIGHT ON MY SMOKE ALARM HAS GONE OUT, WHAT DOES THIS MEAN?
A: If the green light on your smoke detector is not on, it means the AC power has been interrupted to the alarm. Check the circuit breaker and AC wiring to make sure power is still reaching the smoke alarm.
Q: HOW CAN I TELL WHICH SMOKE ALARM IN A MULTI-STATION SYSTEM INITIATED THE ALARM?
A: When interconnected alarms are alarming, the smoke alarm which initiated the alarm, either by test button or sensing smoke, will flash the red LED light approximately once per second. The red LED light on the other non-initiated interconnected smoke detectors will not be lit but will sound the alarm.
Q: HOW MANY SMOKE ALARMS OR DEVICES CAN BE INTERCONNECT AT ONE TIME?
A: The NFPA 72 standard states the interconnect limit is 12 smoke alarms and up to 6 other alarms (heat alarms or carbon monoxide detectors) for a total of 18 total alarms. With 18 alarms interconnected, up to an additional 6 relay modules may be interconnected (for a maximum of 24 devices).
If battery backup alarms and non-battery backup alarms and accessories are mixed in an interconnect system, all devices without battery backup WILL NOT operate during an AC power failure.
CAUTION: USI alarms and accessories should only be interconnected with other USI alarms and accessories. Connecting devices from another manufacturer to USI devices may result in nuisance alarms, failure to alarm, or damage to one or all of the devices in the interconnect system. All interconnected USI alarms should be powered by the same fuse or circuit breaker. Smoke alarms shall not receive their power from a circuit that is protected by a ground fault circuit interrupter. Improper connection will result in damage to the alarm, failure to operate, or a shock hazard.
USI 4-in-1 Hardwired Smart Alarm with Smoke, Fire, CO and Gas Detection MDSCN111 Videos
If you are interested in ordering a large quantity of items you may qualify for volume pricing discounts. Volume Discount Pricing is a great way for customers to save big on large, bulk orders of most items available in our store. Please send a bulk order request to our friendly sales staff so they may create a quote and provide personal service for your order! You will receive a response within 1-2 business days and our office hours are Monday through Friday, 8am-5pm CST.
We make it as easy as possible to ensure you get the lowest prices available:
Let us know what products & the quantities you are interested in.
Get a detailed quote from a dedicated sales rep.
Our warehouse ships directly to you.
You enjoy the savings & are now a preferred customer.
USI 4-in-1 Hardwired Smart Alarm with Smoke, Fire, CO and Gas Detection MDSCN111 Reviews
- Reviewed: 03/22/2022 by John C
I needed a whole house replacement for new construction detectors that were at end of life and got a good deal on upgraded 10 year battery models and got a few more carbon monoxide detectors to cover every bedroom and added a natural gas detector. Replacing the ceiling mount bracket and a couple wiring pig tails was not too hard. Very happy to not have to replace batteries and to have the best protection for my family.
- Reviewed: 03/18/2022 by Bridget L
Very happy with my sales representative and the order I received.
- Reviewed: 02/04/2022 by Roger A
Great alarms that detect Smoke, Heat, Carbon Monoxide and natural Gas
I am so comfortable knowing that the alarms will detect all the hazards mentioned on the Review Heading. We have installed these on the three wood framed homes we have had since 1977 through today. While we have not had them go off in “anger” when we were asleep but we fell much better knowing we have these alarms on every room especially now that we are on our late 70s. They have each lasted over the 7 years stated and generally 8 years or more. We have also had a couple of friends during this who had fires in their homes which were not detected until the fires were really going but they luckily were unhurt but the damage was significant but not too bad. We have had gas cook stove where the pan overflowed and the gas flames were doused and gas was going into the house undetected. Thank God it was detected in time before we were gassed. It is so easy to be playing with the small kids and not smell the gas on another room in the house. A Neighbour jumped over our 6 foot fence between our yards as he realised the alarm was serious. These incidents detected early saved lives / damage to our kitchen. So thanks for the 4 in 1 alarms.
- Reviewed: 10/03/2021 by Nathan T
I purchased two 4 in 1 detectors. Replaced my old detectors and networked together seamlessly.
- Reviewed: 08/03/2021 by franco b
good product and went on easy
- Reviewed: 08/02/2021 by franco b
Easy to install
- Reviewed: 08/02/2021 by Taaseen H
I thought this will be tricky to install but it was much easier to install than I thought. If you have basic knowledge then it's a breeze.
- Reviewed: 07/15/2021 by Danielle A
Very pleased. Easy to install. Working well to date. I would certainly purchase again.
- Reviewed: 06/15/2021 by DAVID L
Perfect transaction from start to finish. From the amount of detailed info on the web site, ease of ordering, great communication and quick delivery, I am a very satisfied customer. Product was exactly as described and a perfect fit. Highly recommended vendor.
- Reviewed: 05/28/2021 by Helen D
While my product was on backorder, Universal keep me informed via email. I apprecialted that. The alarm arrived, was easy to install and works great. I'm a happy customer.
- Reviewed: 05/28/2021 by Michael F
good product/helpful staff
These smoke detectors are excellent, installed as advertised, and hopefully will last another 10 years.
They were backordered I was told at the time I made my order and the folks at Universal Security were very excellent and clear about keeping me informed about the expected delivery date.
- Reviewed: 12/25/2020 by Laura Weisshar
Easy to install connected with the current wiring.
- Reviewed: 12/14/2020 by April Liverman
I am pleased.
All of the smoke detectors work good in my home.
- Reviewed: 08/25/2020 by Brandon
Replaced existing 10+ year old hardwired USI detectors with no rewiring, just needed to swap the base plate. Quick and easy.
- Reviewed: 08/18/2020 by Steve Cannon
I purchased this smoke detector to replace an old one. I bought the same brand and the wires from my old one plugged right in. installation was very simple.
- Reviewed: 08/15/2020 by Amanda Duffy
quick shipping and what I expected.
- Reviewed: 08/13/2020 by John Miller
Simple to install. Works as specified. Delivered on time.
- Reviewed: 07/20/2020 by Paul Chauvin
I installed it myself.
We have gas appliances, so we needed a system that included natural gas detection. Gives us peace of mind.
- Reviewed: 07/16/2020 by Joseph Wyens
Very good service. Product working fine.
Delivered on time.
Thanks for service
- Reviewed: 06/17/2020 by John Earley
Substitute for Smoke and Fire only
Decided when replacing all five of my wired-in smoke and fire alarm to replace sensor closest to my utility room and coincidentally near to my kitchen gas stove top.
I had to change mounting base from prior USI 1208 detector to USI 4-in-1. Took the most time figuring out what breaker had the smoke detectors powered on. But after shutting off power the wiring change was a snap with existing wire nuts.
Now I have a bit more security for CO and NG detection as well as the remaining four smoke and fire alarms, all inter wired together.
- Reviewed: 06/15/2020 by HORACE BOWERS
So far so good. Will be ordering another one
- Reviewed: 05/18/2020 by Joseph Bachir
I am happy with the service and product
- Reviewed: 05/07/2020 by Ricky Davis
Prior alarm was USI and worked properly for ten years. Easy to install/replace with other.
- Reviewed: 05/05/2020 by Jeffrey Karoleski
Good Product and Experience
Product came in a timely manor, replaced an older version with no issue, and appears to all be in working order. Satisfied with the product and company.
- Reviewed: 01/23/2020 by Mark Kennedy
Replaced 20 year old detectors.
- Reviewed: 12/06/2019 by Tommy Jue
Product features without competition
Giving it a top rating because it's a product that integrates all types of safety hazards into one device. Bo other company that I know of has this product offering. Its insurance that is good to have considering all the electronics and gas burning equipment that we have in the home.
- Reviewed: 10/20/2019 by JOSEPHINE Micelli
My previous detectors stopped working and were discontinued..bought 2 of these and connected very easily ...working fine now and would buy again..hope I never need them .
- Reviewed: 09/17/2019 by Ronald Carver
Smoke, Fire, CO and Nat Gas Detector
Piece of mind from a great, reliable product at a great price.
- Reviewed: 08/12/2019 by John Thompson
Plug Compatible Replacement
I bought this to replace a similar existing unit by USI. Best news - its plug-compatible so I just disconnected the old unit which had aged out, updated the base plate in the ceiling with the included new style same size - no painting reqd, and plugged the new unit into the existing wire. The units in the rest of the house tied together electrically all beeped their approval and I got green light thumbs up on all three units. Done.
- Reviewed: 07/13/2019 by Jack Desimone
- Reviewed: 06/25/2019 by Joseph Milano
Replaced old fire alarms. Needed to change the base but otherwise easy install. Have not had the opportunity to test these out as I have never had a fire. The test button works well. All interconnected and work together.
- Reviewed: 06/19/2019 by Dale Steadman
works great installment was easy
- Reviewed: 05/22/2019 by Jim McKinnon
4 in 1 detector
I have looked at many stores for this type of product.I'm glad that I found product. This puts me more at ease. The alarm is set near the furnace. With a hard wired system, this is better.I can sleep in comfort now. Thank you universal security Instruments.
- Reviewed: 05/20/2019 by Greg Stanley
Happy with the product so far. The unit I was replacing is no longer made. This model easily fit into the housing unit.
- Reviewed: 05/05/2019 by Greg Stanley
Great product. Easy to install. No problems since installation.
- Reviewed: 01/22/2019 by Alan Duval
Multi sensor universal alarm
These multi sensor alarms were exactly what I wanted to replace three older wired smoke only alarms from this company. All of their alarms have always performed without any issues for the 17 years that we have been in our home. The time is coming up this year 2019 to replace all of the rest of the smoke alarms. I will be ordering them once again from USI Electric. I highly recommend the alarms from USI.
- Reviewed: 12/17/2018 by Noelle Klibert
- Reviewed: 10/23/2018 by Robert de Vente
Fire and CO2 and natural gas alarm
Fire and CO2 and natural gas alarm. My house heading out dated CO2 fire alarms, this new version also includes natural gas! They help me choose the replacement model that was appropriate for my home system. Thank you for protecting me and my family!
- Reviewed: 10/18/2018 by Jennifer Pasko
We require condo owners to have the 3-in-1 detector, which has since been discontinued. We ordered the new 4-in-1 detectors and they work seamlessly with an additional feature! Ordering more soon.
- Reviewed: 10/15/2018 by Raymond Bacci
Had problems with old units, new units seem to be working great.
- Reviewed: 09/14/2018 by Ray Bacci
have not put up yet -replacing unit that goes off when washing machine is running-will buy another one if it works all right
- Reviewed: 08/22/2018 by Brian Gross
GREAT CUSTOMER SERVICE
TOSH IS A VERY NICE GUY
AND THE PRODUCT IS VERY RELIABLE
- Reviewed: 08/22/2018 by Roger Avery
Great Product that makes my family safe
I have been using this product for several years and this is the first one that failed and needed replacing. BUT this was after the time period guarantee expired. Others have lasted longer but that's just my good fortune. It was very easy to replace but I did have to replace the disc that holds it to the ceiling as the design has been changed to make it easier to lock the alarm to the ceiling. This was provided all I had to do was remove/replace two screws.
- Reviewed: 08/02/2018 by Jonathan Larson
Easy to install and works as advertised. Excellent product I would recommend to anyone.
- Reviewed: 05/30/2018 by Charles Dove
Extremely good value for this many functions. Works with many other USI alarms. Wanted one alarm with CO detection in room with ventless propane fireplace that would communicate with other non CO alarms in the rest of the house that I was replacing. Easy to install, simply wirenut the leads on harness to your boxes wires and all set
- Reviewed: 03/26/2018 by Justin Frederick
This a great to have co and natural gas with a dual sensing alarm. Great peace of mind. Easy to install.
- Reviewed: 02/15/2018 by Yante Gonzalez
- Reviewed: 02/12/2018 by Yante Gonzalez
Excellent Product. Easy to install and work perfect.
- Reviewed: 11/16/2017 by Neidra Akers
This alarm is the best. I would suggest for anyone to purchase it. We now have 3 within our house.
- Reviewed: 08/24/2017 by John Maccio
Pleasure to do business item in stock received right on time and the person I spoke with was very helpful will do business again
- Reviewed: 08/11/2017 by John Scarlata
The alarm was easy to install and is effective for multiple sources of fire, smoke etc
- Reviewed: 07/24/2017 by Rick Rose
So far so good
- Reviewed: 01/02/2017 by John Lemire
I was in need of replacement smoke detectors. I decided to upgrade on detector on each level with the 4-1 detector. Thisent will eventually replace my CO2 detector that I have had for some years. Easy to install using the old wall plates and wire harness.
- Reviewed: 11/04/2016 by Dexter Hernandez
Easy to install. Relief to know my family is protected.
- Reviewed: 09/23/2016 by Thomas Concolino
USI 4-in-1 Hardwired Alarm
Nice product! Was delivered on time and had no damages.
- Reviewed: 09/26/2015 by Richard Kilmer
- Reviewed: 12/13/2014 by Brian Peters
Easy to install
Easy to install and gives me piece of mind.
- Reviewed: 11/02/2014 by Tony Smith
Im a Firefighter
I love it easy to put up and you can hear it in the bed rooms. And I love that it protects against all 4 .