Smoke detector out of date

[Fluke]

I've got two wired-in smoke detectors, one in the hallway downstairs and one on the landing upstairs. The one downstairs has just started chirping, I disconnected it from the base attached to the ceiling to get the battery out and notice that the 'replace by' date is 2018. It's a Ei141 model as shown in this 1 minute video.

https://www.youtube.com/watch?v=z-hWd6_gYxo

Wondering if anyone knows if it's just a case of replacing the bit that you disconnect containing the battery? Or do I need to get a whole new unit (x2) plus an electrician to fit the thing? How seriously must we take these replace by dates anyway?

[Boots]

We had the same issue, with the same model. It has happened twice over the 20 years we've been in the house - there probably was a mix of expiry dates when first installed.

I just bought replacement units from Amazon. On the first occasion I bought a Aico EI141RC unit. On the second occasion I bought Aico EI146e - I can't remember why, perhaps I couldn't source the other type?

In both instances, they just slot in, just like when you have removed to change the battery and refitted. No need to have an electrician.

And they have all activated since - cremated toast.

[csearle]

Wondering if anyone knows if it's just a case of replacing the bit that you disconnect containing the battery? Or do I need to get a whole new unit (x2) plus an electrician to fit the thing? How seriously must we take these replace by dates anyway?

Yes, just slot in a new one yourself. You can get them all over the place e.g. from Screwfix. Put a small slotted screwdriver in the marked place then rock its tip firmly upwards towards the ceiling. Then push the head of the detector away from the screwdriver.

If it is a rental property the requirements became more onerous this year. The batteries have to be internal (i.e. not replaceable) and certain British Standards have to be met. Same for heat and CO detectors. These are more expensive than the replaceable-battery sort. If it is not rented out then you can put up whatever you like (maybe insurers have a view).

How long they still work after the replace by date is unknown. It will depend upon several factors. Not changing them out is the same as not having them. Your choice.

Chris

[Fluke]

Boots, Chris, you've answered my question, I'll get down to Screwfix this morning. Relieved that it's nothing complicated.

[Fluke]

Just to update, went down to Tool Station (such a good shop), bought an Aico Ei146e which came with a Duracell battery included. Fitted it exactly as advised above, just slotted in. What I did notice is that the unit did not have a 'replace by' date like the existing one. Why the existing one has one I've no idea, there doesn't seem to be anything wrong with it, just the battery, but I felt obliged to replace it anyway - just in case there's an insurance issue. Now I know it all works I'll go and get another one tomorrow and replace the one upstairs, so that should be that for a good few years.

[csearle]

What I did notice is that the unit did not have a 'replace by' date like the existing one.

Well that's odd. I've never seen one that hasn't a replace-by date on it. It is usually on the side. C.


https://cdn.aws.toolstation.com/images/ ... /65963.jpg

[csearle]

Why the existing one has one I've no idea, there doesn't seem to be anything wrong with it...

Just as an aside, in an earlier life, I used to write software for (Siemens) optical smoke detectors. They were designed for commercial/industrial use rather than domestic. They had a chamber within, which was connected to the outside air. A bright LED would periodically flash, its light travelling across the chamber. At about 45⁰ to this beam was a phototransistor which could detect light reflections back off of dust particles within the chamber. SIgnals from the phototransistor would be digitised and supplied to the microcontroller. Within this microcontroller the values would be integrated¹ over time. If the result of the integration exceeded a threshold the detector went into the alarm state.

So that light was only reflected back off of dust particles there was an elaborate labyrinth on the opposite side of the chamber to the LED. No light escaped (think black hole ). Anyway after a few years the chamber would very gradually build up dust particles on its surface and these would contribute to a background reflection level even when there was no smoke present. The software did its best to mask this out of its deliberations but every now and then the only solution was to remove the black plastic chamber² and wash/dry it. After this process the background reflection would be low again.

I suspect that with these maintenance-free domestic detectors, where no such maintenance is envisaged, they solve growing false-alarms simply by giving it a replace-by date.

Chris
¹ And also decayed.
² The software triggered a maintenance request when the background reflection exceeded a certain threshold.

[pochisoldi]

I suspect that with these maintenance-free domestic detectors, where no such regular maintenance is envisaged, they solve growing false-alarms simply by giving it a replace-by date.

False alarms are one thing (leading to pulled out batteries/disconnection from the wiring), the more concerning issue is the failure of the thing to go off when a fire really happens.

I think the things are designed to last 10 years, and to fail noisily before then.

And as far as linked alarms are concerned, I'd like to know how I would retro-fit them into a flat with a solid concrete ceiling. (I've never managed to drill a hole any deeper than the depth of the plaster skim).

[csearle]

And as far as linked alarms are concerned, I'd like to know how I would retro-fit them into a flat with a solid concrete ceiling. (I've never managed to drill a hole any deeper than the depth of the plaster skim).

Use a radio base maybe? C.

[RockRabbit]

I'd like to know how I would retro-fit them into a flat with a solid concrete ceiling. (I've never managed to drill a hole any deeper than the depth of the plaster skim).

These should go through solid concrete with a hammer drill.

https://www.screwfix.com/p/dewalt-extre ... -set/88598

[servodude]

I'd like to know how I would retro-fit them into a flat with a solid concrete ceiling. (I've never managed to drill a hole any deeper than the depth of the plaster skim).

These should go through solid concrete with a hammer drill.

https://www.screwfix.com/p/dewalt-extre ... -set/88598

Indeed - the right bit will normally go into anything; and if it doesn't I've probably got the drill running backwards

[Fluke]

What I did notice is that the unit did not have a 'replace by' date like the existing one.

Well that's odd. I've never seen one that hasn't a replace-by date on it. It is usually on the side. C.


https://cdn.aws.toolstation.com/images/ ... /65963.jpg

Yep, that's where it is on the existing one and why I knew it was out of date (by 5 years ) but I've checked again and there is definitely no replace-by date on the new one. I'm picking another up today, I'll check it in the shop and see if it's got one. Without the date why would anyone ever replace it unless it was obviously faulty. hmm.

[9873210]

Yep, that's where it is on the existing one and why I knew it was out of date (by 5 years ) but I've checked again and there is definitely no replace-by date on the new one. I'm picking another up today, I'll check it in the shop and see if it's got one. Without the date why would anyone ever replace it unless it was obviously faulty. hmm.

AIUI some of the newer ones signal end of life with a distinctive LED pattern and by beeping in an unpleasant manner.

[Boots]

I just checked our Aico Ei146e, and it has an expiration date sticker on the side.

[UncleEbenezer]

Indeed - the right bit will normally go into anything; and if it doesn't I've probably got the drill running backwards

I managed to melt a drill bit.

It was when my parents moved house in 1992. The new house - originally servants' quarters for posh regency houses - had serious stone walls. It was thought to be flint that defeated my drill bit while putting up bookshelves for my dad.

[csearle]

Indeed - the right bit will normally go into anything; and if it doesn't I've probably got the drill running backwards

I managed to melt a drill bit.

It was when my parents moved house in 1992. The new house - originally servants' quarters for posh regency houses - had serious stone walls. It was thought to be flint that defeated my drill bit while putting up bookshelves for my dad.

When the drill bit glows you know it is time to switch to an SDS drill bit or glue.