Zone 5 covers windows I hadn't open in years. I was without power for many days and had to open all windows. When I got power back, everything went back to normal except zone 5. It's showing the window is open even after it's been closed. I've tried to reset it but to no avail. What could possibly be the problem?
The problem is with the window sensor or contact. First you say you haven't open said window for years, then you had to open them. Strange but you must have moved or damaged the window contacts / sensor.