Strange Smoke & CO alarm occurence

[CD]

I have a pair of connected EI 151 smoke alarms, must have gone in when the house went up 10 years ago. They both started doing their low alarm squeak in the early hours today, there have been no powers cuts at all. Removing them from the mains & doing a test reveals that the backup batteries are both flat. I then hear a 3rd low battery squeak coming from a room where there is no smoke alarm. I trace this to a CO detector on a cupboard. Coincidence or cause for concern? The boiler wasn't going & it has no pilot light, so no gas burning anywhere. All 3 going at once, what are the chances of that?

CD

[nightjar]

Routine maintenance of emergency systems using rechargeable backup batteries in industrial situations usually involves replacing the batteries every couple of years.

Colin Bignell

[David Lang]

CD wrote;

Assuming all three batteries were installed at the same time and all three detectors draw similar current, it seems logical to me that they should run out at the same time.

Dave

[Christian McArdle]

Then they should be replaced entirely, not just the batteries. The sensors degrade over time and should be replaced about every seven years. There is often an expiry date on the casing. Batteries should be replaced at manufacturer's recommended intervals, which are usually 1 year for alkaline and 5 years for lithium cells.

Quite high, actually. What is worrying is that you waited for the low battery signal. The batteries should be replaced on a schedule and should never get low.

Christian.

[dale hammond]

[dale hammond]

[CD]

Sorry, I wasn't clear in my OP. The smoke detectors are mains powered, with battery back up. The CO detector is a battery one, batteries in CO detectors are not replacable, you need to swap the whole unit. Strange they all went at the same time. I have since found the manual for this model & done the battery test, which confirms they are dead. Off to get new detectors now.

Cheers

CD.

[CD]

You are correct Sir. I'm about to go shopping for new ones.

CD.

[Andrew Gabriel]

Ionisation alarms are supposed to last at least 10 years in service. I have some 20 year old ones which still seem to work fine but aren't any longer in service (actually, the one on my garage is, but it still seems as sensitive as new ones).

CO detector is another matter though. The detector elements are quickly wrecked by standard household chemicals, and you shouldn't assume they'll last more than a year or two. Some have a plug-replaceable detector.

Pick a day each year (like your birthday), and your annual present to yourself is a replacement set of smoke detector batteries.

[Gary Cavie]

The fire brigade round here reccommend changing them when the clocks change - new batteries every 6 months sounds overkill, but the old ones just get used in games, remotes etc, so isn't a problem.

[Andrew Gabriel]

Even after a year, they are still usable, so I would not normally throw them out immediately. However, about 5 years ago, I adapted all my smoke detectors to run from the burglar alarm, so there's no more battery changing now.

[Gel]

Some facts. Sealed in rechargeable will last 10 years; some manufacturers actually Guarantee that eg Kidde Fyrnetics, Aico is 5, Firex 6.

Battery only powered alarms: Zinc Batteries will need changing annually, possibly even more if Optical alarm, as they consume at twice the rate of Ion alarms, as DO CO ALARMS. Good quality alkaline like Duracell give 3 to 4 years in an Ion Alarm; halve for CO and Optical.

Other poster is correct in saying that all smoke alarms should be viewed as having max 10 years life; CO alarms is not 2 years however, but 6 or 7. Many CO alarms now have firmware that shuts down CO alarm after set period; will explain in manual, and emit special warning tones beforehand.

Useful data at

I've found.

Regards garage smokes not recommened there but fixed po> I have a pair of connected EI 151 smoke alarms, must have gone in when