Smoke alarm mystery...

[bongos]

Was rudely awoken at 4.40am this morning by my mains powered smoke alarms going off. After a quick panic and alot of swearing I could find no smoke, no RCBO tripping, no power cuts...what caused this?

Dust anyone?!

They've been installed for 7 months and i've set them off a couple of times cooking but that's it. They are two Kidde mains powered with battery backup, one optical and one ionisation - don't know which one went off to cause the brown trousers incident.

Any ideas?

 

[ericmark]

Spider or fly very small can set off smoke alarms.

 

[jj4091]

Don't the instructions tell you to vac them out on a regular basis for that reason?

 

[mikhailfaradayski]

Spider or fly very small can set off smoke alarms.

im not sure a spider or a fly would be strong enough to press the button to set it off

 

[bernardgreen]

I have been told over the years by three separate sources that mobile phone transmissions from a phone being used close to a fire alarm have been responsible for the fire alarms to trip. Possibly this could also be a problem with domestic smoke alarms.

 

[bongos]

Don't the instructions tell you to vac them out on a regular basis for that reason?

They do say to vac them out but I wouldn't have expected a problem inside of 7 months. It's possible though I suppose...

im not sure a spider or a fly would be strong enough to press the button to set it off

Not even a really big spider?

I have been told over the years by three separate sources that mobile phone transmissions from a phone being used close to a fire alarm have been responsible for the fire alarms to trip. Possibly this could also be a problem with domestic smoke alarms.

Possibly. Although no mobile phones anywhere near them.

 

[Chri5]

Don't they sound if the battery goes botty up

Might be an idea to switch the mains off and see if they all hold up on the batteries. If one fails then it might explain last nights mysterious event.

 

[CEC]

I had a false alarm in a holiday cottage near here. The guests obviously liked to be kept warm as all the windows were shut, the place was roasting, and there was condesation everywhere (the walls were actually wet). I reckon it was the condensation that tripped the alarm. I had to chuck it out as it never worked properly again.

For future reference, with linked alarms, the one that triggers the alarm usually flashes a different colour LED (possibly red?) to all the others.

 

[VanSolo]

A few others have mentioned insects.
Cornflies are a real nuisance as far as smoke detectors are concerned.
Don't know why they are so attracted to them, it's usually light sources.
The little blighters are always at my laptop screen.

 

[olly_k]

This also happened to my Kidde optical / ionisation detector went off about 4 times over a four hour period. Tried vaccing (no fun at 3am) in the end it stopped and works normally ever since. I would vote for a critter or dust too!

 

[Johnmelad502]

Is the wife or one of the kids a secret smoker?

 

[bongos]

Cheers for the suggestions! Not sure which one went off as by the time I looked up and my eyes had focussed they had stopped. Glad to hear i'm not the only one it has happened to though.

I'll have to get the vac out. Seems like the most likely possibility as my house is quite dusty.

I'll try isolating them too though as suggested by Chri5 and seeing if the batteries are knackered and that caused it.