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Pir Positioning


Guest sp1bob

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hi all,

regards of detectors facing windows as James says less likely today to be a problem, and personmally i never had an issue with detectors facing windows (i'll bet that will get a few upset on here :unsure: ).

i prefer to have the pir above a door, that way it don't get covered by a curtain, bookcase with a hat box on top etc. and they dont put shelves or speakers in front of it either usually, which is a much higher incident than any f/a's caused by a pir looking at the glass.

but one thing that still can cause trouble (and often overlooked), sunlight reflected (bounced) of a glass or shinny table directly onto the pir mainly late summer and during by high sun spot activety. a dual-tec will reduce this, but as microwaves penatrate the building fabric it can also on occasion trigger if external movement is detected at the same time.

has been the reason of client's saying 'the alarm never has a problem normally, but it always waits to go wrong while i am on holiday' giving you a real big clue that sun spot activity is the cause :yes:

regs

alan

If you think education is difficult, try being stupid!!!!

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Not if you adjust it correctly... ;)

Hi Alarm Guard

so please tell me how in a 'L' shaped lounge or dinning room, or in a long narrow room (this should get interesting)

regs

alan

If you think education is difficult, try being stupid!!!!

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why not alarm guard

Think of the shape of the "L" and think of the shape of the microwave coverage and you should be able to answer your question.

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Use 2 sensors and adjust correctly..... Check mate I believe good sir... :whistle:

so you would 'face' two mwd devices towards each other would you? when doing so is like pressing two baloons together, you get a spill over of detection into the vacant area adjacent the 'L', so not checkmate more like 'check it mate' B)

i started to think of Jordon then and i've completely lost the thread now

regs

alan

If you think education is difficult, try being stupid!!!!

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Use 2 sensors and adjust correctly..... Check mate I believe good sir... :whistle:

I agree,but you should never have a dualtec with a microwave set so high it can penetrate the building fabric.........false alarm rate riseing me thinks?????

so you would 'face' two mwd devices towards each other would you? when doing so is like pressing two baloons together, you get a spill over of detection into the vacant area adjacent the 'L', so not checkmate more like 'check it mate' B)

i started to think of Jordon then and i've completely lost the thread now

regs

alan

also dual tec should no longer cross talk

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I agree,but you should never have a dualtec with a microwave set so high it can penetrate the building fabric.........false alarm rate riseing me thinks?????

also dual tec should no longer cross talk

hi mjw,

seems a few are msiing the point me and alarm guard are bantering about.

the patern or 'baloon' of a mwd side of the detector will spill through the walls in a narrow room, this is because you need to cover upto the far boundary, so if you have an 'L' shape room to get to the far boundary on each side of the 'L' means the spill over would be into the outside 'inner' of the 'L' which could be a court yard, this may contain a down pipe, so if raining could put the mwd into alarm, then if the pir is tripped say because a fan heater you get an 'unexsplained' false alarm.

now can oi get back to my imagination of Jordans boobs? as they have some reference point, ie an artifical scenario blown out of all preportions :whistle:

regs

alan

If you think education is difficult, try being stupid!!!!

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also dual tec should no longer cross talk

Noticed that the "new" Pyronix d/t's are sticker colour-coded to avoid positioning similar ones opposite one another, thereby causing cross-talk.

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