Eugene's DIY Den Posted October 10, 2017 Share Posted October 10, 2017 So a lot of my contacts need to be replaced, most of them on windows which are never really opened. A few are on doors and windows which are regularly opened. The switches are sticking closed. Is this typical if the reed switches aren't "exercised"?, or did I just get low standard switches when I installed my alarm almost 20 years ago? Quote Talking Tools, a Facebook group for discussing anything tool/DIY related. Link to comment Share on other sites More sharing options...
Amps Posted October 10, 2017 Share Posted October 10, 2017 41 minutes ago, Eugene's DIY Den said: standard switches when I installed my alarm almost 20 years ago? I think these contacts have done you proud. Time to replace them. 2 Quote Link to comment Share on other sites More sharing options...
Eugene's DIY Den Posted October 10, 2017 Author Share Posted October 10, 2017 Two more questions! Do magnets lose their strength over the years. I tested a new contact I replaced with both the old and new magnet. Both contacts opened when the magnet on the window moved outwards 1 cm. It's probably good practice to replace both contact and magnet? Second question: The PVC windows have a chamfered edge, so I can't butt the contact up against the magnet because it would be proud of the window opening and likely to get knocked if anything is passed through the window. At the moment, the contact only opens when the casement is pushed out 1 cm. Tapping the contact hard doesn't seem to open it when the window is closed, so the reed switch seems to be securely closed. Do you think this is good enough, or am I going to have problems down the line with nuisance triggering because the pair aren't close enough? Quote Talking Tools, a Facebook group for discussing anything tool/DIY related. Link to comment Share on other sites More sharing options...
MrHappy Posted October 10, 2017 Share Posted October 10, 2017 46 minutes ago, Eugene's DIY Den said: So a lot of my contacts need to be replaced, most of them on windows which are never really opened. A few are on doors and windows which are regularly opened. The switches are sticking closed. Is this typical if the reed switches aren't "exercised"?, or did I just get low standard switches when I installed my alarm almost 20 years ago? The reed is just little bit of metal in glass tube.... I reckon most of the branded alarm contact manufactures buy in the same Reeds... The gases escapes for the glass tube & they either FA or just fail (open or closed) I suspect those the fail early have been thrown around or the screws knocked in with a hammer when fitted 2 minutes ago, Eugene's DIY Den said: Two more questions! Do magnets lose their strength over the years. I tested a new contact I replaced with both the old and new magnet. Both contacts opened when the magnet on the window moved outwards 1 cm. It's probably good practice to replace both contact and magnet? Second question: The PVC windows have a chamfered edge, so I can't butt the contact up against the magnet because it would be proud of the window opening and likely to get knocked if anything is passed through the window. At the moment, the contact only opens when the casement is pushed out 1 cm. Tapping the contact hard doesn't seem to open it when the window is closed, so the reed switch seems to be securely closed. Do you think this is good enough, or am I going to have problems down the line with nuisance triggering because the pair aren't close enough? IIRC 13mm operating gap, thats look way too far apart 3 Quote Mr Veritas God Link to comment Share on other sites More sharing options...
Eugene's DIY Den Posted October 10, 2017 Author Share Posted October 10, 2017 1 minute ago, MrHappy said: The reed is just little bit of metal in glass tube.... I reckon most of the branded alarm contact manufactures buy in the same Reeds... The gases escapes for the glass tube & they either FA or just fail (open or closed) I suspect those the fail early have been thrown around or the screws knocked in with a hammer when fitted I fitted the contacts, so there was TLC involved! However they seemed to fail after a few years on the windows which weren't opened. The currents involved are only milliamps, so they hardly weld closed? Quote Talking Tools, a Facebook group for discussing anything tool/DIY related. Link to comment Share on other sites More sharing options...
Lwillis Posted October 10, 2017 Share Posted October 10, 2017 26 minutes ago, Eugene's DIY Den said: I fitted the contacts, so there was TLC involved! However they seemed to fail after a few years on the windows which weren't opened. The currents involved are only milliamps, so they hardly weld closed? The metal pins inside the glass tube just doesn’t Spring back. Replace the contacts job done Quote Link to comment Share on other sites More sharing options...
Eugene's DIY Den Posted October 10, 2017 Author Share Posted October 10, 2017 (edited) 52 minutes ago, MrHappy said: IIRC 13mm operating gap, thats look way too far apart The bottom edge of the magnet to the closest edge of the contact is 11mm. Edited October 10, 2017 by Eugene's DIY Den Quote Talking Tools, a Facebook group for discussing anything tool/DIY related. Link to comment Share on other sites More sharing options...
MrHappy Posted October 10, 2017 Share Posted October 10, 2017 3 minutes ago, Eugene's DIY Den said: The bottom edge of the magnet to the closest edge of the contact is 11mm. there on surfaces which are stepped apart, a "chunky contact" does 30-40mm gap I wouldn't fit then in the locations you've got 1 Quote Mr Veritas God Link to comment Share on other sites More sharing options...
Eugene's DIY Den Posted October 10, 2017 Author Share Posted October 10, 2017 (edited) 6 minutes ago, MrHappy said: there on surfaces which are stepped apart, a "chunky contact" does 30-40mm gap I wouldn't fit then in the locations you've got What would be the consequences of spacing the pair this far apart? Edited October 10, 2017 by Eugene's DIY Den Quote Talking Tools, a Facebook group for discussing anything tool/DIY related. Link to comment Share on other sites More sharing options...
MrHappy Posted October 10, 2017 Share Posted October 10, 2017 If the gap is too wide the reed may not close / may open after a period of being set Depending on the case design you mage be able to double up the magnets which give them more "pull" Quote Mr Veritas God Link to comment Share on other sites More sharing options...
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