The Universal Security Instruments MDS300B Smoke and Fire Alarm responds quickly to both fast-flaming and slow-smoldering fires to protect your family against deadly threats in the home. Perfect for new or replacement installations, the MDS300B 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 smoke and fire 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. A Duracell battery (included) operates the alarm and continues protection in the event of a power outage.
This 2-in-1 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 a smoke alarm inside every bedroom, outside every sleeping area and on all levels of the dwelling. The Universal Security Instruments MDS300B Battery-Operated Universal Smoke Sensing Smoke and Fire Alarm comes with a 10 year limited warranty.
* California and New York Residents - Please note this alarm is not compliant with your State's 10 Year Sealed Battery Alarm Legislation Requirements.
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 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: 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.
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I previously bought a 10-year battery warranty smoke detector from another company. It was constantly go off and was very difficult to stop. So I returned the smoke detector and bought this smoke detector and so far it's working with no problems
Universal Smoke & Fire Alarm
Reviewed: 08/18/2021 by John S
Product works as advertised and was easy to install
Best value dual sensor detector
Reviewed: 01/05/2021 by Carl Griffiths
I did a lot of research prior to purchasing 7 of these units for my home. They are the best value dual sensor units on the market and perform really well. I opted for these over the 10yr life battery version as I don't necessrily believe the battery will actually last 10yrs and I will end up having to replace the whole unit. These units come with a Duracell 9V included. I did get one bad unit out of the seven I ordered, the customer service took care of it for me and sent a new one and return label right away.
Reviewed: 01/17/2020 by Daryl Ford
Received the MDS300B and immediately tested it. It is a major improvement over the older, false alarm sensors that were installed in our home during construction. Very pleased with this sensor and will soon be ordering a second.