Reply With Quotesometimes when you mount the detector right up to the cornice you cant get the lid on after.
But yes detectos also have a range of heights where they are efeective. But in a normal house you can put them up near the cornice and you'll be ok
Placement of PIR sensors
I've noticed some installers position PIR sensors about a foot below the ceiling cornice when installing in a corner. Is there a reason for this?
Does a PIR sensor have to be only up to a certain height from the floor to be effective?
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sometimes when you mount the detector right up to the cornice you cant get the lid on after.
But yes detectos also have a range of heights where they are efeective. But in a normal house you can put them up near the cornice and you'll be ok
Always follow the instructions that come supplied with that PIR Detector.
Most installers will put the PIR under the cornice as it's easier for them, keeping in mind this is usually within tollerances as reccomended by manufacturer. If your ceiling is higher then 2.4 meters, the detector should be brought down the wall
Remember, use reed switches on any doors / windows you can
Remember, use reed switches on any doors / windows you can
I tend NOT to use reeds as much as possible. They are neither cost effective nor function effective & reeds that are on doors /windows that are not used very often had a tendancy to stick. They are useful on the entry/exit door as the entry /exit initiator.
I try not to use reeds either unless there is a situation that requires one.
I recon that a single PIR is almost always going to cover more entry points than a single reed.
Just my opinion.
Most PIRs will allow the pcb to be adjusted up or down to fine tune the view area to the height mounted. Walk testing and adjusting until its right.
But as the boys previously wrote, It should be mounted within its advised height range.
I disagree, using only PIR's IMO is not the way to go.
Using reed switches can prove more beneficial to home invasions in this day and age than PIR's alone.
PIR's only offer internal detection. Systems are restricted from being unable to utilise the STAY function due to the design of most homes and common areas. This will mean the only time your house is armed is when you are not there.
Using reed switches can offer perimeter detection on windows and doors. They enable almost every panel with STAY function to arm the perimeter when you are in the home offering round the clock detection irrespective of whether or not the home is occupied.
Another advantage of reed switches is if someone enters your home through a window or door then trips a PIR, you now have an intrusion and a confirmation for the monitoring center staff to easily identify the difference between false alarms and genuine alarms.
Reed switches are as mentioned by George a very important item when installing security sytems and should be used on all entry doors. Using flush mounted reeds ensures that the door is fully close when sealed and they do not false alarm nor do they stick if you use a reliable supplier.
As all security panels have handover zones correct use of a reed switch will ensure better protection if an handover area is breached without the entry door being opened.
As far as installing any equipment it is not hard to first read the instructions and use volumatic sensors that can be adjusted to cover the area you want to be protected. Having used reliable quad PIR's for the last 15 years with no false alarms it all comes down to installing your equipment as per the manufacturer's instructions.
Basically read the relevant standards that apply to installing security systems and the equipments installation instructions and you are on your way to doing it like a professional.
Spot on George, Spot on...... I cannot agree with you more....Originally Posted by intelliGEORGE
Its a shame the "Younger" techs out there dont share the same experience....
yeah i tend to agree with that to, at least you get that intrusion and confirmation that George is on about. Also enables all of your internal devices to be on a handover or instant type zone.
OK , I'll expand on my last post.
I did say I TEND not to use reeds.
I will explain to the customer the pros & cons as I see them , and then if they want reeds they get reeds.
Pros - 1 ) Cheap euipment cost
2 ) Are fairly reliable
3 ) Gives a fair degree of flexability for system
operation
Cons - 1) Can be unreliable if not operated constantly
2) Can be labour intensive to install
3) Can suffer from water problems in heavy rain
4) Will only operate if door/window is opened , not
if glass is removed
5) In most cases they are easily bypassed
6) Will usually result in a larger capacity panel
A couple of scenarios I have come across -
An installation of a Sol 16 with front door reed on zone 1 and 32 reeds for the rest of everything on zone 2. NO PIRs at all.
An MCM Icon 8 with 24 reeds wired back to the panel , not much room left in that box.
Another Sol 16 with a total of 47 reeds wired into 3 zones. These were daisychained "somewere" in the roof - what a wonderful repair job that turned out to be.
And a question for Sydneytech - how do you get on with the new regulation of "ONE" device per zone. Guess we'll see a lot of domestic Challenger installations.
As I said , I explain to the customer & then we usually TEND to keep the number of reeds to a minimum.
There are many panels available that can handle multiple zones, i recently did an installation for a friend, full perimeter reeds, 2 story house, all downstairs windows / doors reed switched & any upstairs windows accessible easily, e.g roof, pergola e.t.c, we also used PIR's in all main traffic areas, garage e.t.c
NX 16 was used, no more then 2 reeds per zone. All pir's on individual zones.
During construction this was THE WAY TO GO, my friend has dogs, and at night they hit partial, arming all windows and doors, they do not have deadlocks on windows.
Reed switches VERY RARELY false alarm, and when a system is monitored provide a multiple activation.
Any installer that talks a client out of having reed switches need's their head red !
Those installers should be shot. I always quote expansion boards to comply with one device per zone.
All of those scenarios could have been easily resolved with an NX-16 expanded to an NX-48 with an LCD keypad.
Again I agree 100%....
Maybe some of you that are too busy should "Hire a Subby" or in Georges case a "Real Subby" I can only imagine your installations are spot on. Great to see some that still care in the details over and above the "yep that works" attitude that the new breed have. Some of the new guys are good but they are very rare.
I must say when I first started in the industry reeds were a common item but
I think people got lazy easier to run a wire to a ceiling mount than down a wall to say an external door , I must admit till i got my first 18 inch drill bit i thought reeds were a pain in the arse to install.
If i ever built a house from scratch would put reeds on all doors and windows
as well as PIRs in required rooms
I would love someone to develop a Ceiling PIR 360 degree with in built Glass break and Smk detector each on a seperate output but i can only dream
With today's technology, you can still offer a wired/wireless solution. You will find that installing wireless reeds works out to be cheaper than labour, and still have the option available. Better to be wired, but even better wireless than no protection at all.
Love the 3 in one ceiling mount idea. Check for a patentmight be worthwhile tassy.
This is the closest I have seen.
Here is one I PhotoChopped earlier....
Last edited by intelliGEORGE; 31-03-08 at 12:29 AM.
good one George i like it
Yep we had to put reed on all external doors at a nursing home to stop midnight wanderings used a nx panel 36 wireless reeds has been working quite well certainly an upgrade on the 6 reeds they originally relied on
I think people are just getting lazy over reeds people i speak to in the states say that nearly every house has at least reeds on front and back door as a minimum
I believe in the states they have more reeds then motion detectors as a rule.
Interesting huh?
WA is the only state I have worked in and found they sell more Reed's with alarm systems than PIR's.
Thankyou all good advice. I'm going with those ceiling mount brackets for the PIRs as it's a little easier to run cable up rather than through the walls. I would not have thought about adding reed switches at all. Where are reed switches best positioned on a door jam? I imagine the top edge of the door is the easiest position to drill up into the wall cavity and run wires through to the roof. Any better ideas?
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