DSC wired window sensor issue


Old 09-22-15, 04:49 AM
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DSC wired window sensor issue

I have several wired sensors at home but only one seems to be having some issue.

Every time I open or close the window the "beep-beep" sound that the alarm does comes in a diff delay. Sometimes you hear it right after opening or closing the window as it should be but sometimes it comes 1-2 minutes later, even 5 mins on other occasions. Its so random...

Also the other night it just went nuts, I heard "beep-beep" like as if it was opening and closing numerous times but the window was never touched...freaky as I thought someone actually opened a door or something (but it was indeed that same zone).

I even taped the magnet connector right onto the sensor to see if that's the issue but it does the same thing.
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Old 09-22-15, 07:58 AM
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I have seen this with wireless contacts, but with wired I'd change the contact and magnet ASAP. These are inexpensive and they do fail on occasion. This should solve 80% of a zone issues.

If you manage your own system hardware and you still have the issue after changing the contact, measure loop resistance open and closed accounting for any EOL resistors that may be in the loop. Temporarily remove the EOL resistors and connect red/green and black/red to get a true loop resistance with no EOLs. Generally it should be well under 100 ohms (like max 20 for longer runs).

Also with the contact disconnected and no EOL resistors and all wires disconnected at both ends, measure resistance of each wire to a good ground to see if there is any water intrusion or damage of the cable to ground. If ground leakage, tag that wire and do not use. You might consider to abandon the whole cable at this point.

If it still does it after the contact is changed with a NEW one, swap two similar type zones (windows contacts) on the panel PCB and see if the issue follows the Window or the zone on the board.

If the board, set that zone to NULL and use a spare zone (assuming ones available). If the Window, use the alternate pair (in quad) or replace the cable (may be easier said than done).

Old 09-22-15, 12:22 PM
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Yeah as you've mentioned to replace the contact is "easy said then done" since all the wires are inside my walls. But it might be my only option. Could it be due to the fact that its a bay-window with two windows which I connected together in order to use one zone (I connected one cable from each connector together and the other cable from each connector goes into my DSC board).
Old 09-23-15, 10:26 AM
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I really try to leave "troubleshooting-by-replacing-parts" as a last resort. The symptoms you describe sounds like a loose connection somewhere in the zone loop. It can be at any of the connections (panel terminals, any splices or connections at the contacts if the contacts have screw terminals) or splices. Flaky switch contacts do happen, but are the rarest cause of this type problem.

I would start by checking all the connections, starting in the panel. Find the two loop wires and give a firm tug. The loop's ground wire probably shares a terminal with one other zone--be sure to tug the single wire, not just the pair. Sometimes a loose wire will "hide" with a well-connected wire(s). If there's any doubt, re-connect with care.

Hopefully you left the splice between the switches where you can access it. I'd check that next. If your switches have lead wires, then those splices should be checked. If they're screw-terminal, check those carefully--a screw connection can look good, but come apart when it's tugged.

If you do replace the switches, I'd use screw-terminal switches. Depending on how you splice your wires, the splices can get stuck in the walls.

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