try 07890 if that doesn't work - just take the cover off the box - yes. it will be noisy for a minute or two while you change the battery which you should get before you open it.
Failing that conatact the manufacturer and ask if they will supply a installation manual for it.
I assume the battery is in the square box that the keypads are wired to ?
If so - put the sytem in engineering mode and replace the battery according to the instructions.
If you dont have a user manual - just type in the model number into google and have a look eg. 500r+ user manual.
Many thanks for that Woodchopper, but I don`t even know how to put it in engineering mode. I tried Google but none of the manuals I saw were of any help. If I start unscrewing the front, TAMPER lights up and I have to screw it back and enter my code. Could you help me any further please?
try 07890 if that doesn't work - just take the cover off the box - yes. it will be noisy for a minute or two while you change the battery which you should get before you open it.
Failing that conatact the manufacturer and ask if they will supply a installation manual for it.