What could cause a false positive with my home alarm system?

[Mr. Clueless]

The panel is a Honeywell ADE Gen4 i believe.

So for the past 3 weeks we've actually been setting the alarm when we leave the house & also go to bed at night. Everything has been fine.

The front door, side door & bathroom window are on those magnetic contacts.
The back bedroom window is on some kind of vibrate sensor
The living room & diner are on motion detector sensors.


I armed the alarm around 11pm last night. At 12:50am this morning the alarm is sounding off.

Shoot out of bed to knock it off & can see it's zone 5 that has tripped ............ the back bedroom with the vibrate sensor.

Go to take a look & nothing untoward. Nothing on the windowsill, nothing on the roof outside. Nothing looks disturbed.

Take a look out the front of the house - cars ok. Now unless someone has gone down the side of the house, opened the side gate, jumped on the roof of the diner to rattle the window, then jumped off the roof as the alarm sounded .... kindly closing the gate on their exit ....

then this was a false positive.

But why?

I don't know when the whole thing (wired setup) was installed but we had the motion detector sensors changed a couple years ago. The magnetic contacts were not changed & neither was the vibrate sensor.

Oh & the bedroom also wasn't left on 'night lock' it was properly closed.

Any ideas?

 

[Handymanjo]

Are you100% sure shock sensor on zone 5 and not a movement sensor
Check all items one by one to make sure what is on each zone

 

[Mr. Clueless]

It's a rectangular sensor on the window. Totally different to the PIR sensors in the living room & diner.

When the bloke installed the new PIRs downstairs he tested out the vibrate sensor & it took a fair old whack to set it off according to my wife.

It wasn't renewed at the time so no idea of its age.

 

[EightyTwo]

Tap the window frame with, say, a screwdriver handle to see when the Viper triggers. It shouldn't trigger without a pretty sharp tap on the far side of the frame. (There is a special, calibrated tool for this but use your best judgement!) If it triggers with the lightest tap or scrape, you need to adjust the sensitivity.

Google some images of vibration sensors to find out which one you've got. It sounds like a Viper GL which is adjusted with a little trimmer pot inside. When you take the cover off, you'll get a tamper...

You may find that the window "creaked" with the temperature change or got hit by a bird/bat. A thunderclap will set them off, too.

Did you ever install CCTV? Have you checked the footage?

 

[Mr. Clueless]

Tap the window frame with, say, a screwdriver handle to see when the Viper triggers. It shouldn't trigger without a pretty sharp tap on the far side of the frame. (There is a special, calibrated tool for this but use your best judgement!) If it triggers with the lightest tap or scrape, you need to adjust the sensitivity.

Google some images of vibration sensors to find out which one you've got. It sounds like a Viper GL which is adjusted with a little trimmer pot inside. When you take the cover off, you'll get a tamper...

You may find that the window "creaked" with the temperature change or got hit by a bird/bat. A thunderclap will set them off, too.

Did you ever install CCTV? Have you checked the footage?

This is the sensor

We did as the installation fella said & armed the alarm Weds night & Thurs night as i was off work on Friday & if it went off again i was to give him a call Friday for him to come out.

It didn't go off. Didn't go off Friday night either.

So i can only assume as he & you said - a bird / bat / temperature change or whatever.

 

[EightyTwo]

It looks a bit like a DSC Shockgard... They have sensitivity adjusters inside, too.

 

[musszzy]

Looking at the state of the shock sensor (cracked & wiring exposed) might be worth rewiring it.