Question about First Alert 9120B Smoke Detector with Batt Backup & SL177 Strobe Kit

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I just replaced the 9v battery in all 8 smoke detectors (First Alert model 9120B). They all show a solid green light, yet continue to take turns chirping. How do I "reset" them?

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SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

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Posted on Jan 02, 2017

  • 34 Answers

SOURCE: smoke detector won't stop chirping.

it may need to be cleaned or it is bad may need to be replaced

Posted on Oct 25, 2009

  • 90 Answers

SOURCE: I replaced the 9 voly battery to the Smoke and


Can you pleas ensure that you have cleaned the unit as well. If it is not broken, that would be the probable cause. You can ask your local fire dept. to assist. They do that for free :-)

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Posted on Apr 23, 2010

  • 134 Answers

SOURCE: Hardwired Kidde Nighthawk co/smoke detector

If the display shows "Lb", the battery is probably low; replace it. If the display shows "Err", push and hold the Peak Level button. Does the display change to "E09"? If so, then you have just been "had" by the grossly under-documented "planned obsolescence feature" called, rather matter-of-factly, "End of Life". This means that ~7 years after first being powered up, the unit will, BY DESIGN, cease to function, forcing you to buy a replacement. Would have been nice of Kidde to include THAT warning on the OUTSIDE of the package. Call their "Hotline" at 1-800-880-6788 and tell them what you think of that policy. If it is still under warranty (5 or 7 years depending on date of manufacture) they should replace it. In any event, buy another one; if they replace your first one you will have twice the protection. Not a bad thing. *Disclaimer: I am not a lawyer, despite the handle. Words to live by: "Every creative act results from a sudden cessation of stupidity." -Edwin H. Land, inventor of the Polaroid Land Camera "The problem can always be solved with the materials in the room." -My college Physics Lab Instructor

Posted on Feb 01, 2011

  • 4736 Answers

SOURCE: My SS785 smoke detector "chirps"

The unit may simply need cleaning. As dust and lint will accumulate on the unit and in the senors.
You can accomplish this with a can of compressed air with a straw nozzle (like you clean your computer with). Carefully remove the cover and blow out all the nooks and crannies of the detector. If you can't remove the cover, stick the straw nozzle into any opening you can see and give it a quick blast of air.

The detector may alarm due to the COLD air from the can. But, should stop once it warms back up.
You should clean all the detectors in the house at least every 6 months.

I find it unusual, that there is no battery backup in your detector. What happens if you have a fire during a power outage?

Posted on Feb 23, 2011

  • 1654 Answers

SOURCE: i want to disable the remote sensor function on

First you need to remove the battery, hold test button down while re-installing battery, when detector beeps,it disarms remote feature. Normal detector then. this should dissable the remote feature. this is a very common complaint. If for some reason it wont turn the remote off get a piece of tape to cover the sensor.
If your happy with this solution a vote for the thumb up would be greatly appreciated. Thanks for using Fix Ya

Posted on Jul 05, 2011

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Hi hislop_amand,

I know this is coming to you late yet I just seen your post and hope the following can still help you or others.

Kind Regards,

FIRST ALERT Model: 9120 9120B

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I hope that this helps.

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