Smoke / C02 Alarm flashing red LED (no alarm)

[Werewolf]

Ah ok, I thought they were all using radiation, didn't know there was another sensor type. I know it's a small amount, but dispose of lots of them and you'd get a bigger amount which is why it seemed daft for them to expire. Also didn't know the sensors had a limited lifespan, so TIL

I only learned the difference a few years back

IIRC early ones were ionising with at the time quite large (compared to todays ones) amounts of a radioactive element due to the sensitivity of the circuit. I've got a feeling at one point they used something like D cells rather than PP3's.
These days you also get optical ones, and heat one - I can't remember the difference for certain but each is good for certain types of fire, so you really want a mix in the house as one (ionising?) is good for fast burning fires that put out a lot of particulates, one is good for slow burning fires/smoldering fires (and things like wiring that is starting to go), whilst the heat alarm won't ever go off from burnt toast so it's the one for the kithen.

We've got an alarm in almost every room, mixing up ionising and optical, with a thermal one in the kitchen (only that one and the upstairs hall are interlinked though).

 

[loftie]

@Werewolf they must have ef'd up the installation in my uni halls then, kitchen one used to go off with burnt toast and the bedroom ones would go off if you had a shower that was too hot or aimed in its general direction with a deoderant can I'd heard.

 

[Werewolf]

I suspect someone cheaped out on the type to use, iirc the heat ones are more expensive by a reasonable amount due to the lower numbers sold

The heat one in our kitchen has never gone, off, unlike a couple of the upstairs ones that go off when the burgers are under the grill