Hello,

Could I have a bit of help please, I've had 2 false alarms in the last 6 months, same zone (Veritas excel, with reflex PIRS's) I am assuming that the alarm is triggered by the door to the room swinging open (Whne I test this it can trigger the PIR)

Would increasing the pulse count make any difference as the door is right on the periphery of the PIR's range ? or should I just change the sensor in case its a fault ? Turning the sensor would not help as it would then be pointing straight at a window.

Any thoughts would be very much appreciated.

Paul

Hi Paul,

The problem isn't with the door swinging open but the heat source it disturbs whilst it's doing so, I suspect either the PIR is looking at, or the door is adjacent to a radiator? Changing the pulse count may help as it only occurs infrequently, but really PIR devices can't cope with such problems. Changing the device to a dual-technology detector (DTEC) will cure it properly.

Alternatively just make sure the door is closed properly, or fit a catch to the door to stop it opening on it own.

Changing the pulse count on a Reflex wont really make much difference.

Like NIKKO suggested "best to change for a Dual Tech.

Or consider re-locating the Reflex, or mask out the area that see`s the door.

fit an optex RX40QZ , and you are guarenteed no problem

A dual-tech won't help if the alarm is occuring as the door opens - the moving door will trigger the microwave part and the heat source will trigger the PIR.

The best solution would be to relocate the detector, however this is also probably the most hassle.

The easiest solution would be to put that zone on "double knock" (ie needs two triggers before generating an alarm) but be aware that the detection performance is compromised.

Forget about the Optex RX40, apart from the fact that it looks like a frog in mating season, it's just a standard cheap Chinese PIR. (Some people wrongly think it is a Quad because of the misleading advertising - it's not it's just a bog standard cheap PIR).

The only sensible solution regarding changing detectors would be to look at something like the Prestige TD (from Texecom) this has two pyro sensors side by side. Both must be triggered to generate an alarm but the likeliehood is that only one would point at the door.

If you can remember to keep the door closed though, that would be the best solution.

MikeR

Thanks for all the advice,

The other thing of note is that the PIR is also pointing at the open fire !! would that affect its performance in any way, or make a false alarm more likely ?

The other thing of note is that the PIR is also pointing at the open fire !! would that affect its performance in any way, or make a false alarm more likely ?

If the fire was lit or even smouldering embers it could certainly generate false alarms (PIRs basically detect heat changes). In theory a very drafty chimney could as well although it's less likely.

I agree with Mike, either move the detector or fit a twin pyro detector.

MarkP

Hello,

One more question

What about fitting a Texecom Mirage Dual Technology PIR, would that do the trick ? I can't find a supplier of the other Texecom DT detector mentioned above.

Thanks very much for all of the advice so far, both times the alarm has gone off its been in the Zone I've mentioned and its been when we've left the fire burning, so it may be the door or it may be the fire, otherwise my alarm is perfect (and I'm using the new Texecom snoke detectors wired in to one of the zones, really good and they do make a hell of a racket I've tested them )

all

Almost certainly the fire.

Dual tech will cure it.

Some people wrongly think it is a Quad because of the misleading advertising - it's not it's just a bog standard cheap PIR

I agree with this. The optex bumff calls it "quad zone logic" which is just fancy software. Last time I looked the pyro still only had three pins so no way its a true quad.