Ei164RC has just start beeping every 40 seconds

[Guest Adam Nicholson]

I have an Ei164RC smoke alarm installed in my kitchen, it has been working fine for about 4 1/2 years since it was fitted, but it has just started to beep every 35-40 seconds.

I have tried hoovering it, and also pressing the test button for 10+ seconds to reset.

Is there anything else I can try or does it need to be replaced?

For information the replacement date on the side is March 2027.

[green-foam]

It probably wants a new back up battery