What ho one and all,

Although I have mains connected smoke / heat alarms fitted to the house, I decided to install a regular, battery operate one at a second high point; it is effective in the dressing room' with access to the bathroom, but is above a void to the f/f space below.

It has been there for over ten years, regularly tested and the battery replaced.

Last night, after having had a bath and five minutes in bed, the alarm activated for no reason. I replaced the battery this morning and again, just now, following my wife washing her hair, it has again, activated. the copy on the rear does state humidity of above 93% but that is certainly not the case.

What would be causing it to activate? Does it mean a replacement?

Thanks and toodle pip

At 10 years they're likely past their expiry date and want binning. Some of the ones we've had in the past have a date sticker on the back so maybe check yours

Thanks. Was not fully aware of the 'sell by date.'

Will replace this one. And will check the mains versions.

In replacing the mains, obviously, one has to buy the complete unit but is it necessary to do a rewire or does the alarm unit just 'plug' into the base with the wiring in place?

Rex- aico easyfits have been pretty much the go to brand for over 20 years, if that’s what you have , as the name suggests it’s a doddle to put new alarms on theexisting bases. However- the old bases will likely have discoloured over time, so not 7nusual for people to change the bases as well. There’s also a wireless extension option, so you could have your extra alarm linked to the wired system. Bit spendy to start off but over 10 years not too bad.

Posted By: RexNot going to go wireless, don't really trust it.

I agree; certainly for something that needs to work in all conceivable circumstances!

We have Aico, and IIRC they use a 4-wire interconnection so maybe the cable would be reusable if I ever had to change brands.

Is it a function of getting older that nothing is easy. Why would they change the base? Since the existing bases are screwed into plasterboard, while not a big job, just some more unnecessary holes in a flimsy material. Can only hope that the mains connections are the same, but that is unlikely!

Have been investigating the Kidde range (that is what I have) and of the three different models currently installed, all now have different numbers or been discontinued. But seems that in reality, I only have two types installed, smoke and a combo smoke/heat in the kitchen.

Posted By: RexNot going to go wireless, don't really trust it.

Through habit I was intending to fit wired alarms on my current project in France, but there are none available here - all the domestic ones are battery only.

Ionisation smoke alarms have been phased out as they had a radiation source in them, which has implications in terms of disposal and some bright spark suggested that it would be possible for a dirty bomb to be constructed using those spurces from umpteen hundred alarms.

Wireless interconnected alarms are currently acceptable as retrofit so long as they have a built in tamper proof sealed battery. I’d prefer not to use them but the trunking runs needed to extend circuits under the post grenfell rules make the radiolink devices much more sensible.

In the Aico range you have the live and neutral supply, along with the interlink conductor. They have a terminal for the earth but it does nothing for the system, just somewhere to terminate the earth.