False alarms from motion detectors


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Old 10-19-22, 11:11 PM
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False alarms from motion detectors

I have a DSC PC5010 - Power832 system in my second home. It has 4 interior motion sensors wired to Zone 1. That system and those 4 motion sensors were in the home when I bought it 15 years ago and I’ve never had a problem with false alarms until now. In the last month, Zone 1 has triggered 3 false alarms while the home was unoccupied.

I have an EyezOn EVL-2DS board installed so I can remotely look at the logs. For each false alarm I see the same series of log entries for Zone 1:
- Motion Sensors Alarm
- Motion Sensors Alarm Restoral
- Motion Sensors Alarm
- Motion Sensors Alarm Restoral
- Motion Sensors Alarm
- Motion Sensors Alarm Restoral
- Swinger Shutdown

Any ideas on what might be the cause of the problem would be appreciated. For now, I’ve bypassed Zone 1. I’ll be going there on Thanksgiving, but getting troubleshooting ideas in advance is helpful.
 

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10-19-22, 11:43 PM
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Welcome to the forums.

A pro installer will never put more than one motion detector on a zone just because of the problem you're having. Four motion detectors and no idea which of the four is causing the alarm.

What I'd recommend is taking a can of air (Dust-off) with you. Take each cover off and blow out the inside of the detector. More than likely you have a spider in one of them.

Another possible problem.... something moving in front of the detector. Curtains across the room moved by the hvac system.
 
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Old 10-19-22, 11:43 PM
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Welcome to the forums.

A pro installer will never put more than one motion detector on a zone just because of the problem you're having. Four motion detectors and no idea which of the four is causing the alarm.

What I'd recommend is taking a can of air (Dust-off) with you. Take each cover off and blow out the inside of the detector. More than likely you have a spider in one of them.

Another possible problem.... something moving in front of the detector. Curtains across the room moved by the hvac system.
 
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Old 10-20-22, 06:24 AM
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And not just the inside. I ran countless service calls where all that was needed was to clean cobwebs from the detector. A spider walking across the outside of the lens or very close to the lens can create an alarm. Any openings in the detector should also be sealed.
 
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Old 10-20-22, 07:40 PM
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Thanks to both of you for the spider tips. I've got someone that will go in tomorrow to check for webs and/or spiders on the outside of the motion detectors. I'll clean out the inside of the motion detectors when I go there next month.
 
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Old 10-23-22, 09:14 AM
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Ultimately, with a mess like this, the only way to narrow it down to a specific detector (if it persists beyond addressing the environment) is to mechanically bypass each detector, one by one, by taking the wires on the alarm relay of the specific detector and shorting them closed.

You do that with each detector, in steps until the false stops.

Another thing that can cause this effect is a weak system battery. It may be good enough that it's not reporting a low battery condition, but still old enough that a minor power flicker is enough to drop the power to the motions enough to make the relay open up. If the battery is more than 5 years old, that wouldn't be a bad thing to check.
 
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Old 10-23-22, 12:19 PM
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Thanks. The one-by-one bypass method sounds painful, especially since the problem is intermittent and the motion detectors are not enabled for most of the time while I’m there at that house. However, they’re enabled full time when I’m not there.

Your other suggestion (weak battery) may be the problem. My previous 12V 7AH batteries have lasted about 3 years before they reported "Battery Trouble” and the current battery at the house with the problem is now 2 years old. Seems like a voltmeter reading on the battery (with and without the transformer plugged in) would be a clue, but I'm not sure what voltages I should expect.
 
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Old 10-23-22, 12:25 PM
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With the charger your should see ~13+ volts, without AC power, a healthy battery will stay above 12.5V under normal standby load, for at least 10-30 minutes without a significant drop.

The bypass test isn't especially difficult, it's just tedious.
 
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Old 10-23-22, 12:44 PM
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Thanks again. I'll check the battery and charger voltages immediately upon my arrival.

The worse thing about the bypass test is waiting (with the motion zone enabled) for the infrequent false alarm to maybe occur.
 
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Old 10-23-22, 12:49 PM
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Yup, did I mention _tedious_? Trust me, especially in the commercial system world, no professional installer does the multiple motions on a single zone more than once or twice, except under extreme protest.
 
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Old 10-23-22, 06:04 PM
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4 motions on Zone 1 makes me suspect the house was originally used as a model home, and the realtor had the system installed to protect the furnishings. Such installations were typically done as cheaply as possible, with a few motion sensors and no window or door sensors, except sometimes the front entry door to initiate a time delay. Does this sound like the system you inherited when you bought the house?

The PC5010 is an 8-zone panel. How many zones are in use, and how many are unused? And is it feasible to move some wires to motions to other zones? Or are they all 4 daisy-chained on the same 4-conductor cable?
 
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Old 10-23-22, 10:06 PM
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You nailed it. It was a model home and has a courtyard and many double doors so 7 zones were used for wired door switches. The windows weren’t alarmed, but I added a PC1508 8-zone expander, a RF1532-433 wireless receiver, a WS4920 wireless extender and many DSC and Ion wireless switches on the windows, garage doors and courtyard gates. I currently have 30 zones used so 2 are unused.

However, I don’t know if the motion detector wires are home-run or daisy-chained and I won’t be there to check until Thanksgiving. Even though I’ve made additions, I left the motion detectors as they were originally because they were trouble-free.

I’m thinking again about MrRonFL’s battery suggestion because the neighbors said they’ve had unusual power fluctuations lately. I’m wondering if the triple trigger and swinger shutdown that I’ve seen in the logs each time are a clue that drooping battery voltage is the culprit.
 
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Old 10-24-22, 02:06 AM
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Have had this very situation come up. Power fluctuations dropping the relays on wired motions backed up by a weak battery.

Cheap fix is to power the motions from a separate power supply with its own battery backup if the motions are Daisy chained.
 
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Old 12-08-22, 11:00 AM
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Follow-up - My zone with 4 motion detectors on it randomly opened again, but this time I was at the house while the zone was open. The problem was that one of those little white (Dolphin) no-strip wire connectors in my panel failed and needed a re-squeeze. That little bugger worked flawlessly for 15 years before it failed. Go figure! Thank y'all for the suggestions.
 
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Old 12-08-22, 05:42 PM
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Good job. Lucky you found that. Thanks for letting us know how you made out.
 
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Old 12-09-22, 06:56 AM
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one of those little white (Dolphin) no-strip wire connectors
If used as intended, they can be a problem. The "teeth' inside that displace the insulation on the conductors don't maintain a good connection. One of the reasons the TELCOs moved away from them. Strip, twist, then put the connector on and they're fine.
 
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Old 12-09-22, 11:14 AM
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Ya got me worried now! This house is unattended most of the time, so false alarms are a big pain. Strip & twist all of them at this point looks to be difficult, so I just re-squeezed all of them with the hope that will prevent another failure.
 
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Old 12-09-22, 09:23 PM
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Your "problem child" may be an "oops", so I wouldn't get too worried. But if siblings pop up later, you're better prepared. If squeezed flat, beans can often be reopened by rotating 90° and squeezing. A pair of common pliers is often sufficient. I wouldn't recommend reusing those beans. If you're replacing them, consider using jelly beans; gel filled versions are easily identified by the plugged small end. The gel helps keep oxygen away from the copper, reducing oxidation.​​​​​​​​​​​​​​​​​​​​​
 
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