Smoke/heat detector problem

[MGB_Roadster]

My house is about seven years old, it has one heat detector (Ei144) and three smoke detectors (Ei141). They're marked "replace by March/May 2018".

Last week the heat detector started chirping, about once a minute, as if the battery was running down. I did a push test and it worked o.k.. I put a new battery in anyway, but it still kept on chirping, so I bought a new detector and fitted it on Monday (sliding it onto the original base). Everything was working hunky dory.

About midnight on Wednesday I heard a chirping from downstairs. It turned out to be one of the smoke detectors. I didn't want to do any testing at that time so I just took the unit off the base, removed the battery and turned the power back on.

Going back to bed there was ANOTHER chirp. This turned out to be a second smoke detector.

It seems a bit far fetched that after seven years without problems three of the four units should fail within a week, the last two within half an hour of each other. I spoke to an electrician who thought it might be a fault in the link cable. He suggested I test this by pressing the Test button on one unit and getting Mrs Roadster to run round and check that all the others were sounding.

All the units sound when one of the test buttons is pressed and the mains is off. When the mains is on all show a green power light, and two of the smoke detectors chirp intermittently.

Any suggestions what might be causing this?

 

[Octopus]

Have you tried hovering them "out" - this is recommended every 3 to 6 months.

That said I can't imagine that this would affect more than one unless you've been doing something in the house which has caused a lot of dust.

 

[tazz]

Good advice on hoovering.....all Detectors weather mains or commercial have life span of 10 years, The 140 series have normal 9v batteries, which should be changed at least every 2 years.
The Ei141 is an ionisation smoke detector, which can be troublesome when contaminated. They should only really be used in bedrooms or lounges.....any 141`s installed in a hallway or landing, I would recommend changing to Ei146 optical detectors.

One final question....what did you do with the old detector you replaced..?

 

[MGB_Roadster]

I've not been doing any decorating or causing dust, but I gave them a go with the Dyson. One of them seems to be behaving now, although the other still chirps.

I'll monitor the one that's working for a few days before deciding on a next step.

I'm a bit confused changing to optical detectors - the manufacturer's instructions say "Ionisation type alarms are less susceptible to dust than optical type alarms.

I've still got the old detector that I replaced - I've read the disposal instructions due to the "tiny amount of radioactive material".

 

[tazz]

Ionisation detectors are sensitive to airbourne carbon particles, hence the reason they false alarm when cooking. Under BS they are advised only to be used in bedrooms, or lounges...All other circulation areas should be fitted with optical detection. With dust, both ionisation and optical can be effected, with neither being better than the other. Both still required hoovering on a regular basis.
The reason I ask if you still have the original detector, is to ensure you have disconnected the battery, I have been called to many homes were a faulty detector was removed, and the homeowners have ended up replacing all the detectors, because they could hear a bleep detector.