Window Screen Tamper

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

=EF=BF=BDNow I have

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!!!!!

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.

Les

"Exposed to weather and the elements is a lot different then submersing them in a tank of water. There's not much chance of the frame filling up with water under normal conditions. I'd think they'd be using a "Hypot" method to test them. That is, there is test equipment available that puts a high potential of voltage across two objects. If there is any path of possible conductivity leakage the Hypot will locate it. Perhaps this is not appropriate with considering the reed switch in the circuit but there's got to be a better way than submersing the screens in water.

So if they submerse them in water and then what? Try to measure a short between the screen frame and the conductor wire? There may not be a short to the frame but if water is captured near a bare wire .... it will corrode.

I know you said you've been using them for a while but maybe they're using a new method, new method or they've got some new people working for them ....... The description of how the problem occurs sure sounds like a corrosion problem to me. Maybe it might be worth it to tear the screen apart yourself. Depends on how much a new screen would cost you. If it were me, I'd want to be the the one to point out to the vendor where his problem was rather than letting them try to find it. If it IS them, you know your not going to get a straight answer.

"Exposed to weather and the elements is a lot different then submersing them in a tank of water. There's not much chance of the frame filling up with water under normal conditions. I'd think they'd be using a "Hypot" method to test them. That is, there is test equipment available that puts a high potential of voltage across two objects. If there is any path of possible conductivity leakage the Hypot will locate it. Perhaps this is not appropriate with considering the reed switch in the circuit but there's got to be a better way than submersing the screens in water.

So if they submerse them in water and then what? Try to measure a short between the screen frame and the conductor wire? There may not be a short to the frame but if water is captured near a bare wire .... it will corrode.

I know you said you've been using them for a while but maybe they're using a new method, new method or they've got some new people working for them ....... The description of how the problem occurs sure sounds like a corrosion problem to me. Maybe it might be worth it to tear the screen apart yourself. Depends on how much a new screen would cost you. If it were me, I'd want to be the the one to point out to the vendor where his problem was rather than letting them try to find it. If it IS them, you know your not going to get a straight answer.

By a 'Hipot Tester' you mean a Megger(brand name). I have used a Megger to test insulation on motor windings to ensure the resistance is within correct values after a motor re-wind and it did not have any possible shorts to the motor case. It may work in this case but I would think it is questionable. I say this because it would seem to me that the insulation at the point of failure would have to be in close proximity to the frame if not touching it. That being said, how can this be assured inside of the frame?? Then again maybe a tolerance value can be developed if you do enough QC and a bell curve can be produced. The voltage on the contacts would not be an issue unless it is directly shorted to the frame.

Thanks for reminding me about the Megger, it has been over 20 years since I used one. Very helpful input.

I am sure that some here are thinking that I am just rambling. Well I am. But my hope is that it may help someone other than me, in some way in the future.

Les

ve used a Megger to

I'm not so sure about that. If there is any resistance ( which there will be) across the contacts of the reed, the Hypot could cause an arc and either burn or weld the contacts together.

There are no moderators here. Ramble away.

Any thoughts about taking a bad screen apart? You probably wouldn't have to destroy the frame to find the problem. You'd just have to trace the wire, inch by inch until you discovered the point(s) of high resistance. Then you could bring the screen back to the vender and actually point at the problem(s). If you're really looking to help others, I'd think that ... that would be a better way to accomplish that end then just writing about it here.

My guess would be that the problem lies in their caulking/sealent application at their solder joints, the type of solder/resin they are using or when they stretch the screen over the edge of the frame ( I'm assuming a metal frame) with the vinyal binding insert. All you need is a single wire submersed in water with a voltage on the wire to cause the problem.

Actually no.

When you connect the Megger leads you would connect to the metal frame and the end of one wire lead. There is no current flow................. unless there is bad wire insulation and a short is produced to the frame at the high voltage potential. It all happens when you turn the crank. If all is in good condition the needle never moves since no current flows.

If current does flow and the reed is destroyed.............. well it was a bad set up to start with so it makes little difference.

Of course the test needs to be performed with the tamper magnet in place to keep the switch closed, otherwise you are only testing one side of the loop.

=EF=BF=BDIf all is

That's right.

The switch is destroyed even if a repairable problem is found.

Yep

First I don't think that the Megger would damage the contacts. But if it did then the Megger is not the tool to use for testing. Using one to evaluate its effectiveness would not be a bad thing. It is done all the time. In some areas they use Crash Test Dummies, durometer, O-scope, or what ever will give some kind of recordable value that can be used.

If the circuit failed, it failed and it needs to be replaced.