Forgotten Code (can i reset?)?

We recently moved into a house with has a veritas 8. For a couple of months we used it then suddenly it kept going of for no reason when we were out. Since then we have stopped using it, and now we want to get it sorted. The problem is we can't remember the 4 digit code. Is there a way we can do this. I have read some of the question on this sight but cant find some directly for this question.

Any help would be massively appreciated.

Mark Davies
March 2008