Electronic Alarms and Home Security Devices - Zone does not fault

I have a DSC alarm system with 6 zones. Recently I noticed that on a zone that contains the windows of three different rooms, if the alarm couplers are opened in one room ( 6 different sensor spots ), the zone does not fault. The green ready to arm light stays on. If the sensor connectors are opened in either of the other 2 rooms, the zone faults. Is the zone 1 big serial loop going from room to room, or can the individual windows in a room be in series, but the rooms as a whole in some type of parallel wired configuration? I know each window is in a serial loop because I did the wiring when I had replacement windows installed, but I can't tell about the wiring between the rooms on the same zone because it is in the walls. Only one pair of wires for the zone comes into the panel. Also the resistors were all removed when the panel was switched out to the DSC panel. I don't know what the original panel was, but all the resistors are lying on the bottom of the panel. However, it previuosly worked this way. Anybody know what can cause a partial zone to act like it's not in the system?

Door and window contacts can fail in stuck open or stuck closed. Essentially, especially on openings that are seldom opened, the tiny contacts can "cold weld". Give the contact(s) in question a sharp rap with the handle of a screwdriver (with the window open). 90% of the time the stuck contact will open.

If so, you will still need to replace it. Once these little reed switches start sticking like that, they tend to fail for good fairly soon.

Pull the contact out of the window and check the continuity on that. Even if u manage to fix it i would say that replace the contact because its not that expensive.

The room in question that does not cause a fault has a triple double-hung window. There are 6 glass break sensors with 6 pull-apart contacts ( 3 sets up and 3 sets on bottom ). Although the top windows are fixed so the contacts are never pulled open, the bottom 3 sets of sensor and contacts are used. Even if cold welding caused a sensor to fail closed, shouldn't opening any of the other 5 still cause the zone to fault? What are the odds of all 6 failing simultaneously? I tried the rapping with screwdriver trick to no avail. Any other suggestions. Thanks for the input.

Hmmm, your description sounds like you have magnetic contacts on the moving sections of the double hung windows, and glass break inpact sensors as well? That's a lot of connections to potentially fail or short. If these contacts all worked before, and no mechanical changes have been made to the windows and contacts.

If you simply never noticed the problem before, then it is possible that this section of the loop is simply wired incorrectly. Really, the easiest way to figure it out, is to set the chime mode on the keypad, and disconnect the contacts on the window until you hear the chime.

Sadly, the "daisy chain" method of routing alarm wiring can lead to these kind of difficult troubleshooting situations. It could easily be a point where the cable has been crushed into a short by the settling and shifting of the house frame.

The windows only have glass break sensors and the chime is on. Rapping any of the sensors or pulling apart the contacts to open the window does not cause the chime to go off at any location around the windows. Unfortunately, when I went to use my multimeter, I discovered that the batteries had leaked and destroyed it. I ordered a new one online, and it should arrive soon.
Maybe then I can get a better handle on what's going on.