Mains smoke alarms going off at random

Wonder can any of you help me with this one.
In the last week the 3 mains wired smoke alarms in our house have gone off at various times at night and in the small hours of the morning.
They went off at 4am his morning and scared the living daylights out of myself,my wife and our daughter,as we all thought the house was on fire,so we jumped into emergency evacuation mode.The noise of all 3 going off at 4am was deafening and rather scary too.

All 3 smoke alarms have duracell batteries in them (as a backup) and we only tested them 10 days ago.

After the smoke alarms going off this morning I decided to flick the trip switch at the consumer board and isolate them off from their mains supply.So they are now just operating on their duracell batteries

Could one of them be faulty and be causing all 3 to sound? Or could there be a bad connection somewhere along the line?
Does anyone why are they activating and going off and does anyone know what I can do to fix the problem?
Thanks.

How old are they?

TTI said:

How old are they?

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Just over a year old.Around 14 months.

Is there a working lifetime for mains smoke alarms?

I just checked... it turns out the radioactive halflife is around 432 years so that won't be an issue: [broken link removed]

You could, if you feel it within your skillset, remove the link wire that the alarms use to communicatie. Then at least the problem alarm should go off on its own and help you zone in on the problem.

TTI said:

I just checked... it turns out the radioactive halflife is around 432 years so that won't be an issue: [broken link removed]

You could, if you feel it within your skillset, remove the link wire that the alarms use to communicatie. Then at least the problem alarm should go off on its own and help you zone in on the problem.

Click to expand...

There was alot of dust and a few small fine little bits of plaster in the heat alarm in the kitchen and also in the smoke alarm in the living room.The smoke alarm on the landing was free of any dust or plaster.
I gave both a good clean out and also hovered out the insides of them too.

Just flicked the trip switch back on the consumer board so heres hoping that was the cause of the problem.

I feel your pain that must have been a nightmare hope its sorted now.

pudds said:

I feel your pain that must have been a nightmare hope its sorted now.

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Well at least we all woke up very fast and our evacuation plan was put through its paces.Emergency rope ladders at the ready and were almost used before I copped that it was a false alarm again.
I also have a 2kg powder fire extinguishers mounted on the wall upstairs on the landing,just incase its ever needed.