DIY Doctor UK DIY Forums

The smoke alarms in my house are completely knackered and need to be replaced, so I bought two Aico EI141RC alarms with mains and battery back up. I now need to fit them. Step 1: turn off breaker on DB so I can wire the new alarms without getting electrocuted. The problem is my smoke alarm and security alarm are on the same breaker, and when I turn it off, my security alarm thinks the power has gone out and sets off an air-raid siren.

The security alarm is a 12 year old Gardtec, I think model 370 581/582. I opened the security control board (which set off the klaxon again) and disconnected the battery in there, but the siren carried on going so there must be another battery somewhere. Is there a more graceful way of disabling the alarm without taking a 4 lb hammer to the siren itself?

The reason your external sounder activates when you turn the mains off is because the alarm panel standby battery is flat and needs to be replaced.
When the mains is turned off the panel standby battery should take over, but as it is flat it can not take over, so your external siren sounds.

You should change the battery as like for like.

Thanks for your help.