Smoke detectors FAQ

Presume they're not 10 year fixed life, then bin it, versions?

Pass. This is about year 6. I wonder if the powered retention is electromagnetic and the retainer has become magnetised.

There is a clear instruction to insert a screwdriver in a slot and then slide off the cover. The batteries are 9V.

Mine lasted 12 years.

Mine had a stack of larger coin cells, all heat-shrinked together.

On closer examination, there is a label saying replace by 2029. I assume this relates to the detector itself rather than anything battery related.>

Could it be that the 'instruction' is to allow you to separate the unit from the base plate? When you say 'batteries' I cannot imagine there would be more than one 9 volt battery. Are you sure the battery is replaceable? Mine is not.

Umm. I'm fairly sure I have had at least one cover off and remember it being difficult.

I'll try your sliding technique tomorrow having had a more thorough search for the instructions. Manufacturers name would be helpful. Nothing visible externally.

Some have a base plate screwed to the ceiling, and the whole alarm comes away from that - twist it or unclip it.

Had a similar expereince recently and the alarm turned out to be one of these:

Yes, they are an absolute pain, just be more forceful until the cover comes off. Once you have removed one it's more obvious how the cover comes off and any more are usually a bit easier.

OK all. Job done:-)

They turned out to be Model ALCO The kitchen has Ei144RC and the others are Ei141RC

As has been suggested, the cover containing the battery is secured by 4 plastic hooks. Poking in the screwdriver releases a latch allowing a bash from your fist to release by sliding the cover 10mm or so. The real trick is to catch the falling part with your third hand while standing on a chair!

New batteries should see them beyond their expiry date. Probably mine as well!

Thanks all contributors.>

I thought that too and wondered if the instructions OP is referring to were to remove the alarm from the ceiling, not to remove the battery from the alarm. Are interlinked alarms not always either non-replaceable battery or hard wired? I think this is the requirement of the Scottish Government.

The difference is that, when you have expired, you won't go beep all night.

We had a CO detector in the kitchen, until recently, which would sound off around 20 minutes _after_ we had finished grilling food. It would then carry on for ages & ages before I could finally get it to shut up. I finally screwdrivered it with exteme prejudice, and ripped the leads off its sounder. Silence is golden.

A very resourceful initiative though personally I would have investigated the source of the carbon monoxide since CO2 has the ability to kill people.

Most of the Fireangel make do that but I do not think they have any that have replaceable batteries. The only advantage of their system is that you can leave the old baseplate in place and simply attach the new alarm to it.

You assume there actually was CO present. I spent some effort to check and found no evidence of it.

1. The only flames around (the grill) would be extinguished 20 minutes before the alarm would sound.
2. We have another CO alarm (for the woodstove in the living room) and on a number of occasions I moved that into the kitchen as a check - no alarm from that one.
3. I would try & silence the bliddy alarm by taking it into a room in a different part of the house and press & hold the shut off button. The alarm would keep on sounding - despite now being nowhere near the putative source of CO.

I should have said CO of course. If you have removed the kitchen alarm, are you not required by law to install a replacement unit, or does this only apply in Scotland?

It’s possible that your reluctant CO alarm worked not by measuring instantaneous levels of the gas, but the accumulated dose over perhaps 30 or 60 minutes, which is of course more dangerous than that of an transitory high reading.

You could have had a very high reading from the grilling process, which when smoothed out over the integration period was nonetheless enough to trigger the warning, although by then was of no danger to you.

The long period of alarm sounding was possibly to this, and when the next integration period resulted in a level that was insufficient to trigger the alarm, it stopped sounding…

There is a British Standard (BS EN 50291-1:2018) for CO detectors which specifies the time/concentration integration characteristics. They are required to ignore brief exposure to CO at moderate levels but not at high levels. The intention is to avoid false alarms from a cigarette being smoked nearby while still responding to sustained low levels. John