Finding false tripping contacts

[Iwilldoit]

I have a wired system and on 2 occasions the alarm has been falsely triggered, during 2 hot weather spells. I am putting it down to a faulty magnetic contact but I have numerous ones on the zone that was triggered, how can I narrow it down as to which one is the iffy one as its an intermittent fault.

And if I make a guess and replace one with a new one then are some contacts better quality than others.
Thank You.

 

[Bigsosij]

Meter the resistance of the reed switches probably find one that's higher than the others. Are they all on one loop or seperate cables to panel

 

[Iwilldoit]

Thanks they are on 1 loop. 2 zones. I dont know if it was hot weather or that it was left for a couple of days armed - or both, but I have done a couple of tests for a few hours at a time now its a bit cooler and it didn't trigger itself. Can not trust it though.

 

[sparkymarka]

Post picture of every set of contacts ( assuming they are surface mount )

 

[Bigsosij]

1 loop 2 zones?

 

[Iwilldoit]

sorry 2 zones each with its own loop. 2 loops/ 2 zones total.

 

[Bigsosij]

What panel is it? How many contacts on each zone

 

[Iwilldoit]

Post picture of every set of contacts ( assuming they are surface mount )

Thank you for your help but could you explain where you are going with this, some are not surface mounts.

 

[Iwilldoit]

I dont want to go into too much security details but its not a well known make and was a DIY fit.
I fitted it about 15 years or more and every now and then I do have a contact fail on it but I have been able to find it because it was a complete fail. This one works - until it doesn't and then trips the alarm but I only get an indication of which out of the 2 zones/loopes the trip is on so I do know which zone /loop its on

 

[sparkymarka]

To see if they are in line ….bad practice to daisy chain contacts as you will never find an intermittent issue with them

 

[Bigsosij]

I would start with the resistance of the loop

 

[Bigsosij]

And also alignment as mentioned

 

[Iwilldoit]

To see if they are in line ….bad practice to daisy chain contacts as you will never find an intermittent issue with them

Yes they are daisy chained -- my bad practice.

 

[Iwilldoit]

On the zone affected I have 5 magnet contacts and 1 PIR. I suppose I could swap them all (faff)
I have tested each contact by opening the window/door and surprised how far the contacts have to be apart before they are tripped so in that respect everything seems fine.
Do the magnets ever wear out / loose their magnitisum
I wonder if I should concentrate on the PIR
The PIR points to a source of sunlight although the sun light is only part of the day and through Venetian blinds.
If the PIR is starting to fail - would strong sunlight cause it to trigger - say coming in and out of clouds. Like I say the two times it has happened it has been a hot day

 

[Bigsosij]

Can u out the pir on its own zone ? Or is it part of the door loop lol