For the first time we have been experiencing very occasional chirrups from the alarm which has brought me to seek help. It has only happened this last couple of days when the weather has been sweltering (for the North East anyway), and only happens when the sun is on the alarm unit.

This has bought much mirth from my neighbours (one of whom is an electrician who has taken a look at it to no avail). I am worried that it will start happening at night time, when my neighbours will loose their affability. Does anybody know if this is a sign of something? I would guess that it is a sign of a battery running down as it is a similar behaviour to the smoke alarm when the battery runs down. I've checked the control panel and there doesn't seem to be anything amis there (after looking at your site I checked for things such as resistors burning out etc.).

All help would be appreciated.

How old is your battery?

Over 4 years old, bin it!

I once had to replace a panel that was showing simillar symptoms. The voltage regulator had perished and was sending over 17 volts to the detectors and bellbox.

We have an optima fitted in a portacabin for our radio club and that would churp now and again and it was the internal sounder (the high level piezo type) ,and i suspect that odd low voltage pulses were triggering it so i just wired a small 12v wire ended bulb accross the terminals and its ok now

Had one customer turn the house upside down looking for a mouse, turned out to be the smoke alarm battery!