Scantronic 9448+ Which Intermiitently Goes Off And

[breff]

Deffo sounds like battery now.

[lawandorder]

Deffo sounds like battery now.

Batteries do get blamed for all kinds of misdimenours and yes it could possibly be the battery but by what mechanisnm does a battery cause an intermittent tamper fault?

[Alarm Protection]

Only ever had 2 of these panels go like that with a duff battery. Normally it was the old rusty bell that was the problem with the tamper switch after doing all checks but it does happen.

[thedcman]

Hi

I intend to call an engineer but my real and only concern is that because it does not happen consistently or predictably, he may not find the real cause of the problem.

The more I think about it, it seems like a situation similar to a 'where you have say a tree branch hitting a wire intermittently because sometimes the wind is too high'. No amount of tests will pick such a situation up unless it occurs when you are actually doing the test or you surmise it after doing a visual check . The main sounder is on the front of the building and they are no trees or anything that would cause such an intermittent error anywhere near it.

I have looked at the wiring that is exposed and can see nothing showing. I have tapped and pulled the wires and the tamper is not triggered .

What would cause such an intermittent error in a battery?

P.S:

All this uncertainty would have been avoided if the tamper circuits had not been wired in series as per the installation manual.

Is it standard to do wire the tampers in series in the industry? Surely it would be easier for everyone concerned, even engineers, to be able to quickly identify exactly which circuit is causing the tamper?

The installation manual says wiring the tamper via a LATCH terminal will give some indication of the tamper so I do not understand why this is not standard and is notnormally done.

[Guest RJBsec]

Intermittent faults can sometimes be difficult to diagnose but equipment is available to alarm engineers to assist with the problem. In all honesty the 9448 isn't a top of the range panel and you get what you pay for, like 'Global Tamper'. A good panel today will use something like a fully supervised loop for circuits, which will indicate faults quite specifically.

[lawandorder]

Hi

I intend to call an engineer but my real and only concern is that because it does not happen consistently or predictably, he may not find the real cause of the problem.

The more I think about it, it seems like a situation similar to a 'where you have say a tree branch hitting a wire intermittently because sometimes the wind is too high'. No amount of tests will pick such a situation up unless it occurs when you are actually doing the test or you surmise it after doing a visual check . The main sounder is on the front of the building and they are no trees or anything that would cause such an intermittent error anywhere near it.

I have looked at the wiring that is exposed and can see nothing showing. I have tapped and pulled the wires and the tamper is not triggered .

What would cause such an intermittent error in a battery?

P.S:

All this uncertainty would have been avoided if the tamper circuits had not been wired in series as per the installation manual.

Is it standard to do wire the tampers in series in the industry? Surely it would be easier for everyone concerned, even engineers, to be able to quickly identify exactly which circuit is causing the tamper?

The installation manual says wiring the tamper via a LATCH terminal will give some indication of the tamper so I do not understand why this is not standard and is notnormally done.

I think the point about using the LATCH terminal is causing some confusion, tampers are never latching. Latching is used when multiple PIRs or other electronic detectors such as vibration or shock detectors are wired on one zone, in the event of an alarm (when the system is set) the respective LED on the detector will illuminate indicating which detector triggered, the LED will stay on until the system is reset.

The above has no bearing on a tamper fault.

As RJB correctly says more sophisticated panels will identify tamper faults by individual zone but the 9448 is a low end panel.

The fact that the fault is intermittent doesn't mean it can't be diagnosed, a good engineer will measure the resistance of all the cables and he will have a good idea as to what the cable should measure based on it's length. If the system was fitted properly the original engineer will have recorded these readings when the system was fitted so in future readings can be compared.

He may even put a meter on the cable then walk around poking things and pulling wires whilst watching for fluctuations in readings, believe me this is everyday stuff to an experienced engineer.

He will also test the battery by applying a load to it whilst measuring it's output voltage.

The fact that the fault doesn't actually occur whilst he is there will not stop him from finding and curing the fault, I would say that a vast majority of faults that alarm engineers deal with on a daily basis are intermittent, it's rare we get the luxury of actually catching a fault in progress.

To be honest, and I'm only speaking from my personal experince, I doubt that this is a battery problem though I would test it as a matter of course and replace it if needed.

A common cause of tamper problems is corroded connections particuarly in external sounders, the resistance of the cable will flutuate depending on conditions and when it gets too high it will cause the alarm to activate but if it's hovering around the threshold it may well reset and be fine for a couple of minutes/hours even months, again a good engineer will find this.

[breff]

I've worked on 100s if not 1000s of 9448s and 9/10 intermittent tamper faults that reset immediately are caused by a faulty battery, believe me.

To OP if your battery is more than 3 years old, get a new one , it needs it anyway. If the tamper keeps happening after you haven't really lost anything.

[hpotter]

What would cause such an intermittent error in a battery?

The battery forms part of the psu smoothing cct (acts like a huge capacitor) apart from its use when mains fails. If the battery is faulty so is the 12v supply to the system, and when the mains flickers, panel triggers tamper.

I've worked on 100s if not 1000s of 9448s and 9/10 intermittent tamper faults that reset immediately are caused by a faulty battery, believe me.

To OP if your battery is more than 3 years old, get a new one , it needs it anyway. If the tamper keeps happening after you haven't really lost anything.

QFA

[lawandorder]

The battery forms part of the psu smoothing cct (acts like a huge capacitor) apart from its use when mains fails. If the battery is faulty so is the 12v supply to the system, and when the mains flickers, panel triggers tamper.

QFA

Perhaps the OP should pull the mains fuse to see if this has any effect?

Must admit I have worked on loads of older Scantronic panels (9100, 9500, 9800, 9600) and my share of 9448s but as I recall they all power up in full alarm not in tamper which would mean that external should be going as well. ( assuming the battery has completely failed and there is a power cut)

But on the other hand a faulty battery can impose a large load on the PSU causing it's voltage to drop which can in trun cause all sorts of things to happen so who knows?

The OP reckons the battery is only about 2 years old but definitely worth checking anyway.

[thedcman]

Thanks for the comments and advice which has allayed many of my fears.

A couple of final questions:

1. the system has not been serviced for a while. Is this type of problem something you would expect to be detected via a normal service, or would i have tell the engineer specifically about it so he can do the detailed checks to diagnose and solve it.

2. i am considering changing and upgrading the control panel. Would I have to change my PIRs etc as well or would any new panel I buy be compatible with them?

3. There are some guidleines and advice on this site for DIY servicing. Are these guideleine the standard actions that you would expect any engineer in the industry to follow, or does it depend on the engineer and company.

Finally.. what does OP mean.. i cannot for the life of me think of anything appropriate..