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Eugene's DIY Den

Magnetic Contacts Sticking on Un-Opened Windows

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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?

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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.

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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?

WP_20171010_005.jpg

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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?

WP_20171010_005.jpg

 

IIRC 13mm operating gap, thats look way too far apart

  • Upvote 3

Mr:)

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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?

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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 

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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 by Eugene's DIY Den

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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 

 

 

  • Upvote 1

Mr:)

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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 by Eugene's DIY Den

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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"

 

 

 


Mr:)

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9 minutes ago, MrHappy said:

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"

 

 

 

I could probably piggy-back the magnets and use long screws. I would prefer to keep the contacts off the chamfer if possible, plus the wiring would have to be  stretched (mightn't be possible) , plus holes where the contacts were, left visible in the window. About 22 pairs are like this.

Edited by Eugene's DIY Den

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3 hours ago, Eugene's DIY Den said:

I could probably piggy-back the magnets and use long screws. I would prefer to keep the contacts off the chamfer if possible, plus the wiring would have to be  stretched (mightn't be possible) , plus holes where the contacts were, left visible in the window. About 22 pairs are like this.

Looking at that frame it's messed up, you could drill in and out from the chamfer if your going enough 

 

If you ever remove the contacts which I doubt you can always have all the upvc repaired these days but if it's your windows you can do as you need to 

 

www.upvcdoctor.co.uk

 

They normally charge for a set of windows in the big scheme of things it's cheaper than trying replace or bodge it yourself 

 

Or similar companies that was an example 

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Going to back to what H said earlier, didn't Ade, or maybe the Knight's chap,  once imply that reeds are no longer made in the UK and the 2 qualities are basically 'USA or China' with nothing inbetween, as it were?

I think he also said that often quantities needed dictated ordering from both areas more often than not, so there is no easy way of knowing where your reed came from in your otherwise 'UK made' contact.

 

I have had loads of failures, usually stuck closed, with those Ventcroft 'Premium' contacts, I don't use them any more, shame as they are a nice looking surface contact with easy EoL and a decent tamper spring.

I use Knights for surface inc. industrial and RSD etc... and Elmdene circular Quickfits for flush.

Edited by datadiffusion

So, I've decided to take my work back underground.... to stop it falling into the wrong hands

 

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I know one company in the South East who makes reeds that are used in the alarm trade


Someone told me I was ignorant and apathetic, I don't know what that means, nor do I care.

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53 minutes ago, magpye said:

I know one company in the South East who makes reeds that are used in the alarm trade

Great for brexit

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15 minutes ago, al-yeti said:

Great for brexit

 

& also brentry ?


Mr:)

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49 minutes ago, MrHappy said:

 

& also brentry ?

New regs yeah?

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34 minutes ago, Eugene's DIY Den said:

After over a year and a half since I posted this, several more contacts have stuck (on windows that are never opened).

I would say common on those standard contacts

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4 minutes ago, al-yeti said:

I would say common on those standard contacts

Anyway I'm adding a few PIR's to act as backup (and implementing an exercise schedule for the windows :rolleyes:).

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11 hours ago, james.wilson said:

Everything should be tested once a month on the user walk test anyway? 

User test every 10years or never 

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Why do you need 22 contacts anyway? You only need to put them on external entries/exits, let the PIR's do their job.

 

Alistair

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