Why did my hard-wired smoke alarm start beeping?
Beeping is to tell you that something is wrong, a smoke detector with a Rechargeable battery should have a life of ten years, the life is calculated by finding the point in time when 50% of a significant sample fail, so it could be considerably less. It is most likely that the battery has failed but it could be a fault in the detection circuit which is constantly monitored in either case the only solution is to replace the unit. Try to buy exactly the same unit so that you can leave the base in position whilst you fit a new head – TURN OFF THE POWER TO THE UNIT BEFORE CHANGING THE HEAD – the unit will bleep if power is turned off to let you know that it is running on the battery is the red light on?(if not you have lost power) if your unit is on a separate fuse / circuit breaker it may beep until the battery runs out so check that you don’t have a supply failure. Your consumer unit should have a sticker marking the protection device of a smoke detector if you find that a CB has tripped