smoke alarm - false triggers

[PhilFromYorkshire]

Hi
I've got an issue with a repeatedly false triggering Kiddie (previously Firex?) KF20 optical smoke alarm.

I'm a landlord and this is a rental property over 3 stories, so it's required to have smoke detectors on every floor (not heat detectors - rental regulations) and these need to be interlinked (building regs for three-storey properties as far as I'm aware).

On the first floor, the alarm is on the landing, which opens up to 3 bedrooms and the bathroom. It seems that optical sensors are much more easily fooled by either steam or just more humid conditions. The sensor has been going off when the tenant uses the shower, but also randomly in the middle of the night when everyone's asleep.

My electrician said he's used Firex for years with no problems, but this is the second one in quick succession he's had giving repeat false alarms. The other was at the top of some cellar stairs - another possibly dampish location. He's going to move the sensor to the far side of the landing, away from the bathroom, in the hope that it helps. The bathroom already has an extractor with a humidity sensor for overrun.

If that doesn't work, then has anyone here got any suggestions? Another brand that is less prone to false triggers? Do any other brands still make the ionisation sensors?

 

[CountryFan]

I presume the wiring has been checked or are these battery operated? We use Aico without much of a failure rate.

 

[PhilFromYorkshire]

I presume the wiring has been checked or are these battery operated? We use Aico without much of a failure rate.

Yes, the spark who fitted it went round last Monday to retest. He found no problems but said he nipped up the terminals and reseated the push-on plugs. Just got a text this morning from the tenant saying it went off today. They are mains powered interlinked with battery backup. I forgot to mention, the spark's first advice was to swap for a new sensor, which I did about 3-4 weeks ago. The whole system is less than a year old and was fitted as part of a rewire.

 

[CountryFan]

Do Kidde have a technical department, maybe speak to them?

If not, then I would maybe swap to Aico and monitor the situation, if still occurs, then has to be a wiring issue. If it stops then I would say issue is the alarms. Hard to say other than that I'm afraid.

 

[PhilFromYorkshire]

Called their technical number - it's just a recorded message saying please use their website to contact them. Can't be doing with that - life's too short.

 

[CountryFan]

Seems you're a bit stuck then I messaged you lodge a complaint with them maybe? Regards the alarms, perhaps try a different brand, such as Aico as I mentioned. They have multi sensor fire alarms which believe work with smoke and heat, so nuisance alarms are rare. Entirely up to you.

There are some recommendations online about humidity levels, dust and spiders webs triggering the existing alarms, but I think you'd have spotted these.

 

[Murdochcat]

Aico are the best and IIRC have a 5 year warranty.

These alarms don’t like dust or small insects so try and give them a good hoover?

 

[flameport]

any suggestions? Another brand that is less prone to false triggers? Do any other brands still make the ionisation sensors?

Make sure that the bathroom extractor is actually extracting, as in it's not blocked and there is somewhere for air to enter the bathroom as well as exit.
Hold a square of toilet paper up to the vent when it's on, should be sucked against the vent and held there, including with the bathroom door and window completely closed.

Excess humidity can trigger optical sensors but it has to be pretty severe to do so, and that doesn't explain it going off in the night when the shower isn't in use.

Ionisation types are basically obsolete now, and you don't want them anyway - they only really react to fast burning flames, and are poor to detect actual smoke from slow smouldering fires.
Most house fires are of the slow smoking variety rather than fierce flames.
They are also excessively prone to false alarms from cooking, including from things like toasters, fryers and just opening the oven door.

Otherwise it's time to sling the existing ones away and fit Aico instead.

My electrician said he's used Firex for years with no problems, but this is the second one in quick succession he's had giving repeat false alarms.

History repeating itself.
Years ago I used to fit the Kidde ones with no problems. Then multiple examples started going off randomly, including in brand new installs, others which were a few months old, and even after several had been replaced under warranty.
No explanation was ever found, the manufacturer seems uninterested, and so that was the end of installing those products.

 

[flameport]

also will add that the Aico ones have built in diagnostics which will tell you when and how often alarms have been going off along with a load of other info such as them being removed from the mounting plate, just in case the tenants have been adjusting the facts about what's been going on.