alarm system goes off after being armed for 12 days consecutively
Hi! I have a DSC PC1500 alarm system that every time I get away from home for vacation in August, gives a false alarm on zone 4 (2 motion detectors) on the 11th or 12th day. Always zone 4, for the past three years. Never had a false alarm except these three.
I have changed the two sensors, but I probably won't know if it solved the problem until next year. I could also swap zone 4 with another zone on the controller board and see if the problem follows, but I would like to know if there are any other possibilities.
I have already ruled out the power to the control panel being accidentally shut off, I have electric baseboard heat (which doesn't run in the summer), I don't have any pets (allergic to them) and I close the blinds before I leave. To my knowledge, there's nothing in the house that could be normally triggering the sensors.
I don't know if it matters, but the cable run between the control panel and the sensors on zone 4 is about 50 feet long (24 AWG 4-color "telephone" wire). I am almost positive that I don't have any rodents, but I still inspected the wires where I can see them and they are not frayed or knicked, and to my knowledge, they don't run near power cables. Nothing on the system is "wireless". Could it be that the wires are too long and/or too thin, causing a slight voltage drop that slowly increases until the 11th day where the voltage can no longer power the motion detectors?
I already have a similar post on the wiring forum, and got some good info there, but unfortunately the info I got is what I had already thought of, so I thought maybe folks on the electronics forum could further help me. Thanks for your help.