My alarm goes off in hot weather?

I am having trouble with my alarm system.In the evenings - when it has been a hot day - my alarm will go off and usually when I enter the code it turns off,with tamper on the display. Tonight it went off and I could not stop the warning beeping stop (not full alarm bells) I took the fuse out the wall but when I pushed it back in the touch pad would not work so I have had to disconnect the terminals inside the box. The beeping has stopped now after 30 mins. My alarm man is on holiday, is there anything I can do to fix the problem? It is an old alarm 12yrs - ADE Optima compact. I dont have the manual to look at troubleshooting and can not find it online