# Forum Home Renovation General Odds & Sods  Smoke Detector chirping at 2.30 am

## cyclic

Had a smoke detector giving out the odd chirp at 2.30 this morning so got out of bed and replaced the battery
It is also hard wired and it kept giving out the chirps at odd intervals.
Put it down to humidity at 95%+ so placed a fan under it and watched tv for an hour to make sure it was right then went back to bed. 
Just a heads up for anyone who comes across the same problem

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## sol381

Yesterday was bloody humid tho so good thinking.
Had one chirp on  a new build we did. They replaced the battery . still chirped. Replaced the smokie. All good. We had a bit of a gas leak onsite yesterday. Just the lever got knocked open accidentally. smokie started to chirp then. Didnt think they picked up gas.  
But, what the hell is actually on tv at 2.30pm.

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## cyclic

> Yesterday was bloody humid tho so good thinking.
> Had one chirp on  a new build we did. They replaced the battery . still chirped. Replaced the smokie. All good. We had a bit of a gas leak onsite yesterday. Just the lever got knocked open accidentally. smokie started to chirp then. Didnt think they picked up gas.  
> But, what the hell is actually on tv at 2.30pm.

  LOL TV at 2.30 am on Fox is same as any other time, repeat movies.
And yes smoke detectors are very sensitive to the point working with oxy acetylene I had to either disconnect them or get Building Managers to isolate them otherwise the Fire Trucks would turn up.

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## MeasureTwice

It wasn't the fact that the fan just blew all the smoke away, was it  :Biggrin:

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## doovalacky

They often beep a couple times after replacing battery. Detection of AC power, detection of good battery. 
New builds not un-common, generally caused by dust inside from the build.

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## phild01

> They often beep a couple times after replacing battery. Detection of AC power, detection of good battery. 
> New builds not un-common, generally caused by dust inside from the build.

  These things can be destroyed by excessive dust, should be covered. I wrecked one with plaster sanding.

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## METRIX

> But, what the hell is actually on tv at 2.30pm.

  Ch 33 SBS FOOD always has something interesting on 24/7  :Biggrin:

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## John2b

Ionisation based smoke detectors are sensitive to gas, but photoelectric detectors shouldn't be (unless made to be dual purpose). 
I don't know why anyone would choose an ionisation based smoke detector because they give a lot of false alarms (e.g. overdone toast) and yet are slow to go off in the case of many real fires because they are not particularly sensitive to the toxic smoke from the burning of the synthetics used in curtains, carpets and sofas, etc. Ionisation detectors have a nuclear symbol on them and contain radioactive Americium, which is formed in nuclear reactors when plutonium is exposed to neutrons. Spent nuclear fuel from power stations contains about 0.01% Americium. Ionisation detectors would have been phased out many decades ago if not for intense political lobbying by the nuclear industry.

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## METRIX

I have a photoelectric in the kitchen, it will go off if the dishwasher is opened at the end of they drying cycle and a heap of steam comes out.

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## John2b

> I have a photoelectric in the kitchen, it will go off if the dishwasher is opened at the end of they drying cycle and a heap of steam comes out.

   Interesting, the steam is obviously interrupting the light beam, which is to be expected. I think the only solution is to move the detector out of the path of the steam. The problem with ionising smoke detectors is they go can off so often that people tend to disconnect them, and even when they are working ionising smoke detectors sometimes won't go off until after people are at risk of asphyxiation when evacuating. I have both types side by side because at the time I installed them I could not easily get information about which is more suitable for ordinary domestic use. I believe some countries are now mandating photoelectric detectors and making ionising detectors non-compliant.

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## cyclic

> Interesting, the steam is obviously interrupting the light beam, which is to be expected. I think the only solution is to move the detector out of the path of the steam. The problem with ionising smoke detectors is they go can off so often that people tend to disconnect them, and even when they are working ionising smoke detectors sometimes won't go off until after people are at risk of asphyxiation when evacuating. I have both types side by side because at the time I installed them I could not easily get information about which is more suitable for ordinary domestic use. I believe some countries are now mandating photoelectric detectors and making ionising detectors non-compliant.

  It was humidity not steam and no problem since and once I ran the fan at it it shut up. 
I fitted a new battery later that morning.
. LOL Phild mentioned dust above and old Builder mate reminded me of the time he was sanding gyprock patches in the Surf Club close to an alarm and the fire truck turned up.

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