fire alarm advice

[1gear]

The fire alarm that's also a CO2 alarm started to beep last night. Which apparently means that its either got a malfunction or its out of date. But the space where the replace by date is empty. So how long are they meant to last? If I remember right it was pretty expensive when we got it because it does both smoke and CO2 and it talks to you aswell as beeping. It was bought in November 2003.
I've not known of a fire alarm go out of date, we had one on the landing for years, but not sure on the CO2 thing.
When I test it will only test the smoke side. The annoying thing is it started to chirp every 30 seconds at 3am! So I had to take it down and pull the batteries out and leave it, which I wasn't keen on doing. There is a smoke alarm upstairs aswell but the one downstairs does the back of the house.
I'll probably be off buying a new one after work today

[border-rider]

Not just a flat battery ?

A quick google suggests that the recommended replacement age is 10 years, due to the increased chance of electronics failing.  The americium source inside will not have dropped enough in activity in that time for the thing to have died.

[Canardly]

They usual start beeping if battery is on the way out

[1gear]

Tried new batteries. However, when there is a low battery it chirps every 60 seconds and says "low battery" so I can be sure its not that. On the back the table says a chirp every 30 seconds is either a malfunction if happened before expiry date, or it need replacing if after. There's still a few years to go until replacement date wise then so it looks like it has malfunctioned

[Euan Uzami]

IF a new one doesn't beep, then there can't be anything to detect, so if the old one beeps, then it must be faulty. In which case you should take it back and get a refund/replacement.
Are you sure its job is to detect CO2 (carbon dioxide), rather than carbon MONoxide (CO) ?

[mrcharly-YHT]

They can get faulty readings due to dust. Try thoroughly blowing out any dust.

[rafletcher]

IF a new one doesn't beep, then there can't be anything to detect, so if the old one beeps, then it must be faulty. In which case you should take it back and get a refund/replacement.
Are you sure its job is to detect CO2 (carbon dioxide), rather than carbon MONoxide (CO) ?

Despite stated life I'd be amazed if a refund/replacement would be available after 8 years.  In any case I think it's the battery that has a possible 10 year life - but that's not guaranteed as it is dependent on usage - many "false alarms" from burnt toast will obvioulsy shorten the life.

As mrcharly says dust can be an issue so maybe a blow through might help.

[1gear]

I'll give running a hoover through it a try.
No idea what gas it detects, we have a boiler near-ish to it which is why we got it. If it was reading high levels in things then it does shout it out. Also when tested it checks both for smoke from fire and that other gas from boiler and this is what it isn't doing. Which makes me think there is a fault because it seems to just be on one side.
It takes 3 AA batteries which do get changed regularly because it tells you to and drives you mad until you do change them. I doubt I'll get refund on something 8 years old

[rafletcher]

Presumably a CO monitor plus particle monitor (smoke)

[mark]

Quick chemistry lesson: CO is carbon monoxide, a colorless, odorless gas produced when various substances are burned (auto fuel, wood, whatever fuel your boiler runs on) that will kill you. It bonds with your body's red blood cells much more readily than oxygen, which the red blood cells are supposed to bond with, so you suffocate as the CO crowds out the oxygen in your system.

CO2 is carbon dioxide, produced when the same substances are burned more completely. AIUI, plants take in CO2 and give off oxygen, animals breathe in oxygen and give off CO2. Too much CO2 in the atmosphere is agreed to contribute to long term climate change, but CO2 itself is not toxic.

I seriously doubt that your fire alarm detects CO2, but it would be a good thing if it detected CO.

[Euan Uzami]

I doubt I'll get refund on something 8 years old

Then sue.