Hot weather tripping reed switches

[Iwilldoit]

I have a very basic system 2 zones with daisy chained contact switches. No PIR
In the summer when its hot I get alarm trips. Problem is I dont know which switch is the cause, some are not lined up for optimal use but the door or window still has to be opened an inch before it tripped.
I have 5 on the zone that is tripping two of them are inset in the door the others are as the photo.
Is there a way to test each switch to find one that maybe is a bit weaker or something
Thank you.

Thank you

 

[Bear2Biker]

I've got those mounted inside on front & back UPVC door frames, both get outside full sun morning/evening & had a similar problem, turned out the screws were working loose due to expansion & contraction & alarm or tamper would go off at 10:15 every night as it cooled down !

The solution was to use a couple of spring or star washers on each screw, I did have to put slightly longer but flat thin head screws in, no recurrence in the last 6 years.

Not sure using a multimeter to test would detect any faults as you'd disturb the problem wires, you could just go ahead & add the springy washers.

 

[Iwilldoit]

That's a great tip and advice thanks I will try that.
Also i read somewhere that teenagers slamming doors can loosen the contacts and yes not through teenagers but with all the doors and windows open I do have an internal door with a recessed switch and that door has been slamming shut with the wind through the house. So I will also have a look at that one too.

 

[Iwilldoit]

Looking at the contacts I can not see how the screw could become loose enough to trigger but am willing to try.

I have some new contacts and looking through an eye glass I can see the reeds are closed and touching but when offer up the magnet I can not see the reeds separating. Or does it need the power going through it as I am just trying in my hand unconnected.

 

[Bear2Biker]

Its "extra" low voltage usually 12v sometimes 16-24v and draws very little current, the "reeds" hardly need to move at all for separation, normally they are contained in low vacuum glass tubes.

These can be subject to vibration from passing or constant traffic or door slamming depending on how they are mounted and to what, ie: something dense that will transmit vibration, so can crack or break (especially with age/temperature changes) which affects alignment of the reed contact surface.

Sometimes using a magnet and holding the sensor to your ear you can hear it "plink" as it opens & closes