Door Sensors don't set off alarm

[c1ayton]

Hi,

First time caller, long term listener.

I have 2 wireless door contacts (one on the front door, one on the back). The alarm lets me arm it and does all the normal irritating sounds likes it's fine but doesn't notice when I open either door any more. Now, i'm not too fussy but having a home security system that doesn't realise doors are opening is a bit crappy.

The keypad is a Scantronic 9751 and the sensors have CooperSecurity printed on them. The PIR sensor thing works fine and sets the alarm off.

I've not had any error messages at all warning of faulty sensors or low batteries or anything. I thought about changing the batteries in the sensors but wasn't sure if the alarm would simply communicate again with them or if it would need recalibrating in some way.

Any help would be gratefully received

Thanks

 

[EightyTwo]

Do the little LEDs on the transmitters flash 4 times when you open or close the door? If they do, it looks like the contact is working but the signal isn't making it to the RFX (or the RFX has "forgotten" the transmitters).

If not, open the transmitter up and see if they flash and you get a tamper. If that works, check that the magnet is operating the reed switch - you might need to fit a new door contact. If there is no tamper,remove the battery or batteries for at least 5 minutes and fit new one(s). you don't need to worry about them re-communicating or "calibration".

If you can't fix it, let us know which type of transmitter you have (old one with a rounded end and 2xAAA batts or new one with 45deg screw in the end and a lithium CR2 batt) and whether you are using an external contact (magnet and wired contact) or just the magnet with the internal reed.

 

[EightyTwo]

I guess you fixed it then...

 

[c1ayton]

Thanks so much for your advice. Sorry for the delay in posting a reply.

Yes it was just the batteries! The batteries in all 3 sensors were flat! Had CR2 batteries in them.

As soon as I put a new battery in, the alarm sounded.

 

[RF Lighting]

Good old wireless. Doesn't even let you know when the detectors stop working

 

[EightyTwo]

You should have had a message about the low batteries. Why not check the log to see when it first started. (Enter your code, then 5. Use 1 to go back and 3 to go forwards in time.) You should see "Z12 LOW BAT" or something similar.

There could also be "RF SUP FAIL" (Radio Frequency SUPervisor FAIL) but this may have been turned off in your system.

Write the date on the new batteries (or put a sticker on the transmitter) so that you have an idea how long they last. Then you can replace them before they run out! The manufacturer reckons on about 15 months so most installers will replace them at the annual service. However, I have known them to last longer on doors/windows that are rarely used.

 

[bernardgreen]

You should have had a message about the low batteries.

To get that message the sensor has to realise it's battery is nearly exhausted and send the low battery message while it still has enough power to reach the panel.

With a two way communicating system the panel would be checking the sensors by asking each one for a status report and if a sensor did not reply then the panel would [1] alert the user and [2] not allow the alarm to be set until the failed sensor had been dealt with.

Worse case in one way communications is when a door frame is replaced and the sensor goes into the skip with the old door frame. The panel will never know that sensor has been taken away.

 

[Europlex]

You should have had a message about the low batteries.

It does give that, (a Pro system) has to be actioned though.