Hi. I did try these instructions already and they did not work. By master code I presume you mean the code we enter when we want to deactivate the alarm. So as you said, I put this code in, then 8, then 02, then my new 4 digit code twice. It does nothing. Can you suggest anything else?
That did not work either. I have looked on the internet and found a manual. It says try 42 , then 1 for user codes, so I am going to give that a try, I will let you know how I get on.