Reasons why sensor generates alarm signal

[Guest Gimmick]

Aaaaah !! It's so nice and refreshing to actually hear from installation companies that talk sense, when it comes to false alarms and detectors. At our Helpline we speak to a high volume of engineers that go on the principle: "it false alarmed, so changed the detector".

When we ask the question "what tests or checks have you done to locate the source of the problem", the answer is often; "nothing. It false alarmed so I changed it . . I'm just concerned that it has false alarmed again . . so called you guys".

So . . no tests for AC induced, voltage brown-out issues, cable condition tests or any attempt to 'move' the fault around the system. Just swap it out.

I have to agree (seeing is how I omitted that from my previous post), that AC induced noise is a huge problem for detectors. I could be clever here and mention that one of our detectors uses software and a patented pyro element to filter out noise, but that would be silly. . .lol. Anyone who has used our new detectors has seen the improvements themselves.

Those guys at ACT should be given knighthoods for the work they have done, since pretty much every "untracable" false alarm source I have dealt with has been resolved with connection of the 12v and mains filters.

Hell, I sometimes get engineers calling the Helpline that want to know what to do . . as soon as they walk on site. "It false alarmed . . what should I check for".

Scary really.

[Service Engineer]

It helps fault finding if the customer can remember any details about the conditions prior to any activation.

I always ask a few routine questions like:,

"was the cat/dog in",

"was that window open?",

"what time does the postman come",

"what time does the heating swith on/off",

"who put that ??????? there",

Unfortunatly I find that some customers while I `m asking these questions are a little hesitant to answer, it`s as if they know they might have done something wrong but wont admit it.

I always check for induced AC and the other obvious stuff when installing, and if required ill change the site spec and alter the siting of detectors to more suitable locations if I feel their might be a potental problem with its specified location, (the easiest place to fit a sensor is often NOT the best).

I agree with all above who state that a detector doesnt false alarm, something must have triggered it. Unless its faulty.

[CompostCORNER]

Just reading Gimmicks post a little further up where he agrees with Pete. Theres plenty of common sense tips there that should be considered or put into practice on every installation. Another tip which is useful and not widely known. In summer, out in country villages, I've had problems with those very tiny black creatures getting inside the detectors. Closer inspection indicates they actually get through the microscopic gaps in the lens or where the front cover connects to the back. Something that turned out to be a massive help from a preventative point of view is a small smear of Petroleum Gel around any edges where microscopic insects could gain entry. So install your detector and run a small smear of the gel around the full detector.

We actually did a test in a customers house and the gel stopped the little buggers dead. I think the creatures are commonly known as thunder flies. You can get hundreds or even thousands inside detectors. CROW SRP200 detectors used to allow these creatures entry around the lens edges where it clipped into the PIR front cover. It would be nice to see a PIR thats manufactured with a moulded integral lens and grommet around the edge where the front clips on. In fact, a waterproof detector design for internal installation wouldn't be such a bad Idea provided the cable entry holes are filled with a non conductive filler like silicone. If water cannot get in, neither would little creatures.

Tony

[markthespark]

Aaah, we get similar problems with these little buggers getting into smoke detectors and giving unwanted alarms. Some are better than others right enough. We have a site with about 120 of one particular (crappy) make. Customer won't splash out on a whole site replacement so having to do a bit at a time. You could always tell summer had arrived cause there's a fire engine parked outside the site

[markthespark]

P.S. We call them Thripps but I've heard them called corn thripps, corn flies, field lice, among other (less polite) things.

[Guest]

a pir that does'nt fa....   thats why all alarm co's use this same kit is it??

you will always get fa's for nar,if i knew the answer id be very very rich....

here's hoping!!!!!!!!!!!!!!!!

False alarms don't exist though. Theres no such thing. Something caused the alarm. It's up to us, the installers to use our experience to figure out what caused it. Ring David grant at ACT meters and he'll tell you theres no such thing as a false alarm.

Theres too many people in our trade who turn up on a call-out when an alarm has supposedly falsed and come away from that job with the same phrase on their job sheet.....

'Cause of alarm:- Environmental'

If a draught caused the alarm, remedy it then. Charging the punter £70 just to reset their alarm is scandallous. Move the detector if need be. Fit a quad or dualtec instead of a standard PIR. Get the punter to draught proof the door your detector is facing. Tell the punters to secure the doors inside the building whilst the alarm is in use.

'Cause of alarm:- Spider'

Bung the bloody holes up around and in the detector then. Inform the punter that it won't hurt the detector if they brush away the cobbwebs.

'Cause of alarm:- UNKNOWN'

You need sacking if you put that on your sheet. lol

Then theres those who add 'Double Knock' to the panel programming for an offending detector. The cheaters way out!

Theres always a cause. We have to find it. If you install decent gear, install it correctly, add all the filters and gadgets AND instruct the punter on how to operate the alarm in a fool proof manner that even a small child can grasp, and properly maintain the alarm on a regular basis, you can virtually guarantee that the alarm will never ever false.

Anyone else here who agrees??

Tony

all standard stuff,but still fa's go on..i take it none of your systems fa then..

ps.here we go again

[Guest BRIAN]

even if the ac induced reading is below 0.5v for the sake of a couple of quid i always fit a act1313, seems pointless going back a few weeks later on a false alarm that could have been avoided in the 1st place !!!