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Smart smoke detector from Nest Labs, the creator of the Nest Learning Thermostat.

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Why does the smoke alarm go off for no reason.

The smoke alarm goes off for nothing. It's summer here, all the doors are open, not a wisp of smoke around, yet it goes off several times a night. My question is can I take this apart and clean the sensor? The unit is a few years old, and we heat with wood so I'm wondering if there's a buildup on the sensor that can be removed. Thanks in advance.

Answered! View the answer I have this problem too

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Thanks for the answer.

Checking the batteries was the first thing I did and they all tested good. Right at the top of the scale good, but. I might try putting in a fresh set just in case.

Thanks again.


On a summer night with windows open, small insects may come through the screen. Attracted by the light on the smoke detector, they can set it off. Spray screens and the detector with bug spray. Yes, I learned this the hard way!


Please note that many issues are when you do not replace with Energiser L91 batteries. This is the only battery that is recommended for this device.

I had no end of issues when putting new Duracell batteries with reports of low battery etc with 100% good Duracell batteries.

Nest support states that only Energiser L91 is supported.


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Change the battery. A low battery will trigger it.

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Hi there.

Your anwer is quite short.

Of course tlyour statement could be true, but my second thought is:

A Nest Protect is permanently connected to AC power. The 3 lithium cells have a lifespan of at least 5 years.

Moreover, the NEST Protect designers would be quite stupid to sound a firewarning because of a battery-faillure, instead of a warning that says: ‘please replace batteries’.

Go figure: there will be not even ONE test engineer that will let such a stupid design flaw unnoticed!

I had this false alarm problem already in 2 unit (both version 1) only after 2 years of continuous operation.

One of them has been sent back to Nest, and they were so nice to send me a replacement u it (version 2 !!)

The second Nest Protect (verdion 1) failed 1 month ago. To test your ‘replace batteries’ solution, I wwill just put new lithium batteries in that second failed unit, and will for sure report back about the result.



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Just for clarity:

The batteries in these are for backup purposes only when the main power fails. All detectors that are hardwired that have battery backup work this way. The user will be alerted to the batteries starting to fail so that they can be changed. While the lithium batteries have a 5 year or greater life, their actual lifetime will depend on how much they are used. The detector will have a monitoring circuit to detect a failing battery.

While I couldn't find it directly, since the detector has a "split-spectrum" detector, I am assuming that it is a photo-electric detector which is less prone to false alarms due to steam and dust. If the detector continues to produce false alarms, replace it.


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Robin Wilkinson will be eternally grateful.
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