I ordered some contacts off ebay for my concord 4 system and every few months I come home to an alarm triggered only to find out the sensor is no longer detecting a closed circuit ( detects open though) This has happened with 4 dif sensors all around the house.

The sensor model is GE NX454 MICRO WIRELESS DOOR WINDOW CONTACT .

I have changed the batteries, removed and readded the sensors with the same result. Does anyone have any suggestions? Or do I need to just purchase some new sensors?

 

These were pretty much the workhorse standard transmitter, for a long time. The odds of the actual switch mechanism failing is pretty low. They do have a tamper switch in the battery compartment, that can fail, and cause the transmitter to show as open.

Since you are buying these from a source where you don't know if you are getting "new old stock" or even used devices, it's hard to judge the situation.

 

Thanks MrRonFL.

They are used sensors but they were all working for months after I installed them.

That tamper switch still gets triggered when I open the battery compartment so it appears to me they should be working but it just does not seem to recognize when the sensors are in the closed possision only the open.

Its almost as if they become half un-paired.

 

Ron, I think you're thinking of the 60-362 / NX650 sensors, that take a 1/2AA lithium cell.

This is the NX454 "Micro" sensors that are tinier and use a 2032 coin cell. I've never actually worked with one, but the data sheet for it states that the sensor should be located within 100 feet of the Receiver/Control Panel, which means it has significantly less range than the 60-362 / NX650.

@rufunky: If 100 feet is the nominal range, it _might_ be that your Concord 4 system has been operating at the marginal edge of its range for months and some environmental factor just pushed your RF reception into the red. It might be doing it intermittently.

One particular case I remember was a customer who rearranged his bedroom furniture and within 12 hours, half the sensors in his house started having supervisory issues.i.e., the control was no longer hearing those sensors hourly supervisory signals. Of course, he didn't connect moving his furniture with the alarm system problems--only an experienced tech would think of that---so he called his alarm company.

When I got there, I found he'd moved his dresser w/large mirror to a different wall of his bedroom, and his Control Panel/Receiver was mounted on a closet wall of another bedroom, and was directly behind that mirror. For RF purposes, a mirror may as well be a steel plate, and it blocked all RF signals in that half of the house.

Less obvious changes in RF environment might be some strong radio source starting up in your neighborhood. If your RF reception is marginal to begin with, it could push reception over the edge intermittently.

This might not be your problem, but the shorter range of the "micro" sensors is one reason I've always avoided using them.

 

Thanks, ChosunOne. Interesting and definitely something I will keep in mind. I have a feeling these sensors are just flaking out on me though.

I have tried to delete them and re-add them back to the system while right next to the panel. They allow me to re-add them by means of opening the battery compartment but again, the closed-circuit part seems to have died as it is nonresponsive.

 

It does sound like several of the sensors have an intermittent problem.

Just to be clear, when you say you re-add them "right next to the panel", you're talking about the Concord 4 panel, not the keypad, right? I only ask because it's a common User error to think of the Alpha Keypad as "the Panel". In alarm jargon, we always mean the Control Panel when we refer to The Panel, and in the case of GE Panels, that's where the RF Receiver is. Keypads might be the other end of the house.

 

Oh yes, I should have been more clear. I was indeed speaking of the control panel. Just really strange they are all dying off in the same exact manner...