How sensitive are PIR's

[caveman2]

A friend of mine had an alarm system fitted - an Infinite Prime with 5 PIR's and a door sensor.
Since it was fitted he has had problems with false alarms from the south facing rear of his house. When recalled the engineer never suggested a Dual PIR but scratched his head and just played with the programmer.
He has got over the problem with blinds and me re-activating (I'm the neighbour) during the evening if he's away.
The programmer has been interfered with so much that he is unsure what zone is what.
Trying to help I read the manual and performed a "walk test" and found only 4 active zones and tested them and documented each one and told him of the one not programmed.
The thing I find puzzling and would like an answer to is how sensitive should they be. On testing them I found that I could dance around for ages in front of them without activation yet could trigger them if standing still and only moving slightly.
Could someone explain if that is the norm. Thanks

 

[bernardgreen]

As this is apparently a wireless alarm the PIRs depend on batteries for power and this requires battery economy methods. One of those methods is to put the PIR to sleep for a few minutes after it has sent a message saying motion detected. Hence it will appear to be in-sensitive to motion for several minutes.

It is un-likely that there is a dual tech sensor that is compatible with the wireless protocol of this alarm.

 

[caveman2]

As this is apparently a wireless alarm the PIRs depend on batteries for power and this requires battery economy methods. One of those methods is to put the PIR to sleep for a few minutes after it has sent a message saying motion detected. Hence it will appear to be in-sensitive to motion for several minutes.

It is un-likely that there is a dual tech sensor that is compatible with the wireless protocol of this alarm.

Thank you for a very easy to understand explanation. Do you have any recommendations for an alarm system that I may fit to my place that would be wireless and have a Dual Tec PIR for the rear of my house.
I considered the Yale for ease but they too don't have Dual Tec's. I'd be happy to spend a little more say £350.

 

[sparkymarka]

Fit a hybrid part hardwired part wireless if some parts are not accessible , eg Texecom premier they do a wireless dt
Hardwired will be better in the long run !

 

[bernardgreen]

I would never recommend wireless unless it was impossible to install wires. Wireless is for when one or more of the sensors are mobile and cannot be connected by wires.

If it has to be wireless then use a system that has two way communication between panel and sensors. One way systems can be set with sensors missing and protected doors open because the panel cannot ask the sensors to report their status.

Another problem with domestic wireless systems is that they operate on licence exempt radio frequencies that are shared by many other systems. Baby monitors, car key fobs to name but two. These will interfere with the communications in other system using licence exempt frequencies. In some wireless alarm systems the Bell box will on detecting prolonged interference go into full alarm. This appears to be a false alarm and may result in the owner having to turn of the jamming detection. If the system is then intentionally jammed the sensors cannot alert the bell and it will not sound when the criminal breaks into the property.

 

[EightyTwo]

You may be able to adjust the "pulse count" in the PIR to reduce the sensitivity. Also, consider relocating the detectors so that they are not pointing at windows or radiators/fires?