Interlinked Smoke Alarms

Alas no... it might work but there is no guarantee. Stick to the same brand as already fitted.

Read what is written. Mixing and matching makes probably won't work but the OP intends to buy two new alarms and replace the two old ones.

AFAIK all mains interlinked alarms use 3 core and earth so it would just be a case of wiring in the new bases as per their instructions.

Yup, I see your point, although he did not say how many alarms there are in total.

If there are only two, and he is replacing both, then I agree that will be fine.

You may even find if they have a standardised base, you can just swap the alarms and leave the old bases.

In my house, when this started happening with one of the alarms, I could only silence all three by replacing the batteries in all three. Then, finally, the chirping ceased.

MM

Mine chirp every 30s when the battery is low. Typically this happens in the middle of the night. When it happened last time I had no spare batteries and discovered that, even when the battery was removed, the chirping continued.

I did this and even replaced an ionization alarm with an optical one to reduce false alarms.

Mark

The chirping often happens in the middle of the night as that is when the temperature of the house drops, that temperatrure drop also drops the voltage on the battery and the alarm starts to chirp (it detects the low voltage on the battery).

It goes without saying that removing the battery removes all voltage from the battery and so the alarm sees the voltage as low regardless of temperature:-)

Cheers

On Saturday 23 November 2013 14:28 ARW wrote in uk.d-i-y:

Makes sense and a most useful snippet - ta!

And not hugely obvious - I've seen batteries drop voltage badly outdoors in winter, but would not have assumped that a cool night indoors could make enough difference.

Note to self - remember to change the batteries more often.

Just buy rechargables.

On Tuesday 26 November 2013 17:21 Adrian wrote in uk.d-i-y:

Which are almost completely useless for this type of application, with a nominal cell voltage of 1.2V and lower when it's cold.

And have a nasty habit of retaining a decent voltage that disappears rapidly when you put a load on, like the trying to sound the alarm...

On Tuesday 26 November 2013 17:52 Dave Liquorice wrote in uk.d-i-y:

Yep - I went through a phase once of NiCds in lots of things.

TV remotes seemed to last a week between charges.

Torches were useless - could never find a bulb with a voltage that worked "right" - either too dim or blew in a few days.

Rechargeables are great for things designed to use them, but until someone gets a cell chemistry that can get near to 1.5V, they will never be much good as a swap in for primary cells.

The worst choice for this job. The rechargable battery will lose it's voltage faster than a cheap alkaline battery.

Very poor choice for a smoke alarm. Their high auto discharge rate manes they don't last well in low current draw applications. Their low voltage if more likely to trigger a low batter alarm in the first place.

That would last longer than the alarm itself. However the instructions say to use only high quality alkali batteries, but that may be rubbish. IIRC it says only Duracell and one other brand.

Unless its a type of alarm that can keep the batteries charged up?...