BRK Brands 9120B Hardwire Smoke Alarm with Battery Backup
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Tools and Hardware Reviews of BRK Brands 9120B Hardwire Smoke Alarm with Battery Backup
Customer Review: Smoke Alarm user Unfriendly!
Summary: 1 Stars
Our house in The Villages came with these alarms installed. The other niight at 10 PM one of these units began chirping intermittently. Since it was installed next to the ceiling I had to climb an 8 foot ladder to remove the unit and replace what I concluded was a failing backup battery. Swinging out the battery door, I removed the old 9V unit only to discover the exact same replacement battery would NOT fit into the battery compartment. I will go to the hardware store for advice today, but this company has no battery install information on its website, nor is there the traditional install diagram on the unit. Their slogan is "Designed with the Contractor in Mind" Guess so. They certainly haven't thought about the end user! Customer Review: Not Happy
Summary: 1 Stars
Ordered a 9120B, received a 9120........Dont buy from Amazon I get ripped off time and time againCustomer Review: Another alarm clock
Summary: 1 Stars
Our electrical contractor installed about six of these in the house and they all beep at random intervals. I tested the batteries and they are all strong. I now have to look into replacing these at my expense. First Alert should be ashamed.Customer Review: Going insane
Summary: 1 Stars
Ditto to the first review of this product. Batteries in these things seem to only last a week at best. I have replaced all 6 batteries in just the first 3 weeks of living here!
But that is not the worst of it. Aside from getting an annoying beep every once in a while for the battery itself, occasionly, the actual smoke alarm (always around midnight) goes off for no particular reason. It is 3 beeps, indicating smoke. And the 3 beeps occurs 3 times in a row, just long enough to wake up the entire house, since they are interconnected and all go off at the same time. I went throughout the house, and there is no sign at all of any fire or smoke. I don't even have a fireplace! Unless you want to be tortured on a regular basis, stay away from this detector.
Customer Review: So these are no better than the 4120B?
Summary: 2 Stars
I was about to buy a set of these, because they are supposed to be an upgrade to the discontinued 4120B. My 3 year old house was fitted with those by the builder. We've only ever had one night of full-on false alarms (which happened at 2 am, 3 am, 4am...) a couple of years ago. Now they've started chirping during the early hours. Our HOA meetings often have people moaning about the crappy alarm clock smoke detectors that were fitted to all of the houses in our subdivision.
Thanks, Amazon reviewers for saving my money. I'm an electrical engineer with several years' analogue and digital circuit board design experience. To say that these alarms can be set off by "power substation switching" is a poor excuse for a bad design. Consumer electronics should be designed to work properly in the environment they are intended to be used in. This is clearly not the case with these things. Being connected permanently to a 115V AC supply means they will be subject to supply noise, which shouldn't cause them to malfunction.
(Star rating given for 4120B model)
Update... I changed all the batteries in the chirping units and it cured that problem. I tested the batteries that I took out, and they all show up as being full on a cheap tester. However, the batteries are pretty well spent - put one in something that actually draws some current for just a few minutes (e.g. a guitar effects pedal) and it will give up the ghost. They seem to only chirp at night and in the winter when it gets cold in the roof void above the alarm. I suspect the cold air makes the battery voltage drop just enough to make the alarm think the battery is dead - which it basically is. Not sure what these AC-powered alarms do to kill an alkaline battery in less than 3 years when alkaline batteries have a shelf life of 5 years. They must take a tiny amount of current from the battery, even while on AC power.