Sounds like you have a bunch of maintenance to do.
Your panel battery is shot, It shouldn't read less than 12V, and I'd assume that you have a device with a low battery as well.
I believe the FA 142 is essentially a rebadged V-15P, but since I'm not a FA dealer, I can't give you an exact answer. The procedure posted in the sticky should provide you a point to go work from.
Hi there...just read your response on this 142C model and I have the same issue. I just moved into a house here and it has the 142C system installed, but there was no knowledge transfer due to the way the original owner died. Botton line, I have no way to program my system short of calling a shop. I do not have the master code. I must start with creating a new master code, then with the user guide I downloaded I can go from there. Can you help? Thanx MichialT