Wired sensors tripping

[ElkridgeTerp]

I have an old school HAI OmniPro (not II) that I installed 13 years ago.   The wired security sensor on one of my exterior doors has begun to trip in error on occasions.  This happens pretty infrequently- maybe three times in the past six months, but that's three times too many!  The sensor is a button type rather than a bar type.  The two sides are still perfectly aligned.  This has happened before on my system with a particular window.  I'm embarrassed to say that I "fixed" it by disconnecting this one particular sensor from the OmniPro controller board.  This is also a wired rather than wireless sensor.
 
Any ideas what causes these failures?  The fact that the failures are infrequent is more frustrating because I can't just says something has completely failed.  
 
Thanks to the community in advance for reading and thinking about my issue.

 

[ano]

Sensors do go bad.  Why don't you just change it for a new one?  They are pretty inexpensive. You can also check the value that PC access displays for that zone.  That can also tell you if you may have a problem, but if the sensor is 13 years old, I'd certainly change that first.

 

[ElkridgeTerp]

Thanks ano.  Wouldn't think that something as simple as the sensor itself could go bad.  Also seem to overlook the obvious.  I'll order new sensors.  Thanks again.

 

[WCG]

I too had a Ghost zone on an upstairs bathroom window. I put the sensor on a different zone and after a few months the issue followed so this confirmed to me it was either a sensor or the wiring. Installed a new contact and hoped for success. The next month it falsed again, I tracked it down to a drywall screw the just barely nicked the cable.

During this ordeal I had changed the instructions with the central station to not dispatch on the problem zone, false alarms are pricey in California. Best of luck.

 

[Del91574]

Doors also go out of alignment over time...they expand/contract and you don't mention if this is a recessed magnetic or mechanical pushbutton contact. Could be a magnet heading south (though a stretch).
 
Also, poor splices are usually a good source of havoc over time.

 

[Desert_AIP]

Can a reed switch fail internally due to metal fatigue from repeated open and close cycles?

 

[gizzmo]

Not likely but if the glass breaks or cracks, yes. Most likely cause other than the switch is poor or corroded connections. Like Del said, mechanical switches have even more issues.

 

[Del91574]

reed switches have duty cycles in the millions. Usually falses are environmental or caused by the media (cabling).

 

[Desert_AIP]

reed switches have duty cycles in the millions. Usually falses are environmental or caused by the media (cabling).

Well, with kids going in and out and in and out all day...it adds up.

 

[Del91574]

I have contacts installed in commercial buildings with public accessing them non-stop....for 30+ years on the same contacts. Relays are a different ball of wax.

 

[TechGeek]

You either have a problem with a faulty sensor or damaged wiring. You could remove the sensor and short the wires at the door to determine which. Also check the resistance of the wire run to verify proper resistance to the loop. Is the magnet installed in a metal door? A magnet installed in a metal door will become weak over time. Either way, a new contact is inexpensive and is worth the cost in replacing the hassle factor , in my opinion
 

 

[Del91574]

A magnet in a metal door does not become weak over time. What happens is the steel compresses the lines of flux from the magnet and that affects the gap of the contact. The 3/8-3/4" adapters or 3/4" contacts just provide a buffer for steel adjacent to the magnet.