*SIGH*!!
This is the first time I recall seeing this thread. Don't know how I missed it when Leon first posted it in 2018. I'd love it if Leon came back on, because what s/he describes puzzles me. For one thing, Leon mentions "changing all the batteries", but doesn't say what batteries s/he changed...hardwired zones don't use devices with batteries, so it leaves me wondering if he changed batteries in the wireless devices (on wireless Zones), or if his "hardwired" zones are actually wireless zones---not the first time I've encountered Users who didn't know the difference. They usually don't have to, until something goes wrong, but you need to know the difference if you're going to troubleshoot.
So I ask: Is your issue
exactly the same, i.e., did you change batteries on devices on hardwired zones; or on wireless zones that had no problems to begin with? Unfortunately, Leon doesn't seem available to ask about what exactly was done, so I need a description from you, if you actually have
exactly the same issue.
Another puzzling thing,
No, if I power down the system and then restart the zones are closed and then one by one they open.
If you also have this symptom, then it's highly likely that the zones in question are wireless. When a Control Panel (the Paradox MG5050 in this case) first powers up, it immediately sees the status ("normal" or "faulted,", i.e., open or closed) of its hardwired zones. The Control Panel does NOT see the status of any wireless zones because wireless devices don't transmit their status continuously. Wireless devices transmit status when a door/window is opened or closed; OR if no door/window activity, it transmits a "check-in" every hour or so (time varies with brand, but usually an hour, give or take a few minutes), and the Check-in carries the open/close status (among other things).
When the Control (aka the "Panel) first boots up, all wireless zones assume a "Normal" status, regardless of the actual status of doors/windows/motion/sound device on the zone. When the zones get around to Check-in (or when someone walks through a motion sensor's coverage etc), or opens/closes a door/window, then the Control updates the zone's status.
That's with wireless zones. I've never seen any hardwired zone give that same symptom, and certainly not several at the same time. So I strongly suspect that Leon had some wireless zones that s/he
believed were hardwired.
So I'm going to assume you also have a Paradox MG5050, and some zones are showing open when doors/windows are closed; and that other zones are behaving normally. What zone numbers are giving you a problem?
There are functionally 3 types of zones: (1) On-board zones, with wires connected to the MG5050 Panel itself, (2)hardwired expansion zones, that use an Expansion module connected to the Panel, usually in the steel cabinet with the Panel, and (3) wireless expansion zones, that also use a module to add their zones to the system. If your problem zone numbers are all consecutive (e.g., "8, 9, 10, 11, etc), then the problem is likely to be an expansion module or even the main MG5050 PCB. With multiple zones suddenly malfunctioning at the same time, it's unlikely that the wires are the problem.
Rather than build more "If...Then" logic trees, I'll wait to hear what zones are misbehaving and what, if anything, you've tried. Remember, the specific zone numbers can be indicative.