We may have found other answers which could help you.
Click here for Alarm Light Lit
Gardtec 800 system error code -t after power cut?
Gardtec 300/500 series- key pad shows 1u. ?
where can i buy a replacement battery?
Gardtec 800 with a battery/fuse failure?
Gardtec cpx lost chime yet again?
change battery on gardtec800?