Home Alarm Siren When Not Set

[grantone]

Our home alarm siren went off today while not set and we were home, no power cut, just random.

Entering the code on the panel did not turn off the siren. Turning off the alarm power supply made the siren tone slightly wobble, but it kept on going. Opening the panel below the keypad triggered a separate (tamper?) alarm which did turn off with the code, but the main siren kept on. Disconnecting the backup battery inside the panel finally turned the siren off.

System is probably 15 years old, we bought the house 5 years ago and never use the alarm (insured on basis of no alarm), it's not made any noise before while we've been here. Keen to avoid spending any money on a system we don't use.

- Is it OK to just leave the dedicated power supply off at the consumer unit and the backup battery disconnected rather than being properly decommissioned?
- Is the likely cause a 15 year-old backup battery?

(My poor neighbours have a 1 week old baby who didn't enjoy 10 minutes of siren while I faffed about.)

[crmcatee]

More than likely the battery voltage has dropped sufficiently to trip the tamper circuit.

Replace it and all should be good again.

[grumpyscot]

crmcatee said:

More than likely the battery voltage has dropped sufficiently to trip the tamper circuit.

Replace it and all should be good again.

Exactly what happened to me. New battery and all was sorted.

[grantone]

Thanks, will give it a go.