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Re: Window Screen Tamper

"Jim" <alarminex@xxxxxxx> wrote in message
On May 22, 9:11?pm, "ABLE1" <royboynos...@xxxxxxxxxxxxx> wrote:
> "nick markowitz" <nmarkow...@xxxxxxxxx> wrote in message
> news:d0660178-3bff-4948-9132-5d8c055e9788@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> On May 22, 5:55 pm, "ABLE1" <royboynos...@xxxxxxxxxxxxx> wrote:
> > Hey all,
> > I have a customer with alarm window screens. One of the screens has high
> > resistance on the loop. I have been told that it due to a bad tamper
> > switch. Presently the resistance is 125 ohms. A couple of weeks ago it
> > was
> > 14 ohms.
> > My question is if I am reading this resistance what is going on with the
> > tamper switch?? And what will happen long term. Will it eventually go
> > open
> > or will the resistance go to K ohms or M ohms??
> > TIA
> > Les
> > You probably have a corroded switch and it will get worse. screen
> > needs replaced.
> Hi Nick,
> Thanks for the response. ?There is a whole lot more to this story. ?I
> installed 5 screens at this house about 2 years ago. ?Since that time I
> have
> had to get 4 of the screens repaired. ?One twice and two once. ?Now I have
> another.
> The last time was about 3 months ago and at that time I had the screen
> company take all five of them and repair the one and check the others. ?I
> was told that they placed all of them in a tank of water and all was good.
> When I got them back and before install the resistance was from 3-5 ohms.
> Then another alarm two weeks ago. ?This is the one that was repaired about
> 1
> year ago.
> I have these screens on wireless sensors NX-650's and when the resistance
> climbs it is an alarm. ?I just swapped out the old transmitters with the
> new
> version that requires a 4.7k resistor to be in series with the contact.
> ?My
> hope is that the additional resistance of a bad tamper will not cause an
> alarm as before. ?I have tested the transmitter with a pot and increased
> the
> resistance up to 10k without a trigger.
> If I understand it correctly the "tamper" is supposed to be a "magnetic
> reed
> switch" wired in series with the screen wiring. ?What is going on that I
> would failure so many times on so few screens?? ?Is it that the reed
> switches are not of good quality and have leaked thus causing corrosion or
> that the solder connection to the reed switch leads have gone bad?? ?How
> should I specify that the repair be made to "hopefully" stop this from
> happening again.
> I know I need to get the screen repaired, but, I am just trying to
> understand what is going on to make a decision as to what my next move
> should be.
> It is all rather frustrating to say the least.
> Any additional thoughts now that you have "the rest of the story" would be
> appreciated.
> Thanks,
> Les-

Hi Les,
This may sound sarcastic but it isn't meant that way.

My suggestion is to find a new screen company.

I've had screens in for decades without any "resistance" problem.

And WHY are they testing their screens by putting them in a tank of
water, of all things??\

I can only presume that if this is the way that they test their
screens, you're not the only one who's having this problem. The
screens likely have a hollow frame and I don't see how they could
possibly know that they were getting all the water out of the frame.
All you need is one exposed wire in a water solution, with voltage on
the wire and you've got an ideal situation for electrolysis to take
place. As the wire corrodes the resistance gets higher.

Jeeeeeeeze ..... absolutely amazing!!!!!

No offense taken Jim.  Thanks for the response.  I have considered all that
you have said before posting my questions.  I posted here to confirm or deny
my concerns.

As for testing in a tank of water I don't see that as being much of an
issue.  The screens are in the elements such as rain and snow anyhow.  The
wiring should be waterproof to be completely sealed from the weather.  You
don't get corrosion on your car battery terminals unless there is a slightly
loose connection.  That being said, the problem of corrosion is still the
issue.  If there is a failure due to what ever is used to seal the reed
switch or solder joints that is what I am trying to understand.

I have quite a number of screens in from this same vendor without an issue,
most for longer than 8 to 10 years.  These screens are still under warrantee
at this time.  I was hoping that someone here may have had similar problems
and could lend some insight as to the specifics of what could be going on.

Again thanks for the input.


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