Magnetic window switch trouble

Old 05-02-16, 03:40 PM
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Magnetic window switch trouble

I purchased a home that is around 27 years old. The owners claimed they never used the alarm. All of the windows have Amseco magnet switches. I purchased a new Vista 20P alarm panel and 6160RF keypad to replace an outdated Ademco unit that had no parts available and would not power up. Today I started by trying to trace each wire that was going to the old control panel. Most wires are labeled as to which door or window that went to. However, the front door, which has a physical contact switch, is the only one I could verify with my ohm-meter. All of the window and door magnetic switches show open, even when window or door is closed. They also read open when window is opened. I can see the switches and magnets on each window. Is it possible that the magnets could go bad over time? Or possibly someone could have cut some wires, but every magnetic sensor on every window shows open circuit. Any ideas on what to try next.
Old 05-02-16, 04:17 PM
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If it's all of the windows, I'd say that there is a problem with the lead going to the alarm control box. First, make sure you have it hooked up right.

I'm a window guy, not an alarm guy... but in many of the houses I have worked on, the windows are all wired in series, meaning that if one window goes out they all go out. Not every house is wired individually to tell you exactly what window or what door is open. Sometimes they are wired by zones, which at least narrows it down for you. But if ALL the windows are non functioning, I would start by checking continuity from the wire at the control box to the closest window. If you can find a sensor that's loose, pull it out and cross the wires... that would make it read closed. If needed, buy some wire so that you can make a jumper. You will likely also need some wire to help you test continuity.
Old 05-02-16, 06:37 PM
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Do you have access to the terminals on the window switches ?
If you do..... they should should show a short when the window is closed.

If they don't..... make sure the magnet and switch is within like a 1/4" of an inch or the switch won't close. If the magnet is close to the switch and the switch still shows open... the switch is bad.

It wouldn't be the first time several went bad.... a lightning strike nearby can wipe them out.
I've had houses lose many on a lightning strike nearby.
Old 05-05-16, 10:56 PM
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What is the nomenclature of the old Ademco panel you're replacing? 27 years ago is about the time Ademco marketed the Vector panel (Ademco 4152) for a year or two, IIRC. If your old panel was/is a 4152 Vector, this would be the time to mention it.
Old 05-06-16, 02:58 PM
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Correction, there were two Vector models: The Vector 2000 (4152) and Vector 3000 (4153), an upgraded version with more zones and a couple extra features.

Both used multiplex point-module wiring and devices, and if you had a Vector panel, then you can't use the wiring for a Vista-20P. You would have options to upgrade, but I'm not going to get into that unless I know if we're working with old Vector wiring and old 4190 point modules.

If your old panel was a 4150, 4160 or 4180 or even an early Vista series, then we can continue trying to troubleshoot as before.
Old 05-07-16, 06:59 AM
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Another possibility:
27 years ago some "old timers" were still installing mechanical magnetic contacts (Ademco 39 for example) intended for use on relay based panels (higher current through the loop). They might work with electronic panels (lower loop current), if they were relatively new. Their "unsealed" contacts build up resistance over time and the cumulative effect causes false alarms with electronic panels.

If these are classic surface-mount contacts, use a magnet to activate the contacts while listening for the definite "CLACK" of a mechanical contact.
Old 05-07-16, 04:57 PM
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37 years ago would have been 1990-ish. In my area, the old Ademco #39s were pretty much no longer installed by the early 1980 and out of use except for existing systems. We'd replace them with reed switches in old systems for any excuse because they tended to add resistance to the old single-zone circuits that had dozens of contacts on one loop.

But it was pretty rare to see a new installation in 1990 that used #39-type contacts. At least in the DC area.

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