False Alarms....

[Guest mikechids]

Hi,

Getting some problems with false alarms from one PIR at work. Here`s the story...

We have(had!) a 360 PIR above a fire door on the shopfloor. It false alarmed a few times and was changed twice to new detectors. (There are no hanging boards around it - learnt that on already!). One of the engineer suggested that their wasn`t sufficent voltage at the PIR, so we had an extra power supply put in. (Electricain involved etc...).

Still False alarms... Next we changed it to a 360 Dual tech (turned right down)... another false alarm.....another engineer......installed a normal PIR, beside the door covering a smaller area (replacing the 360 completely)..... another false alarm couple of night ago...

Must be fault somewhere else? What should they be doing?

System is galaxy 500, PIR is wired to a RIO, PIR is 30m from RIO.

Mike

[PJF]

I would fit a dual tech, if your door is say front RHS of the shop then I would fit it front LHS looking in towards the opposite corner(rear RHS).

If an engineer had the sence to check the voltage then hopefully he checked the resistance of the cable as well, so I would say it must be down to the enviroment.

[antinode]

Could be some form of interferance/noise on the cable to the detector, especially as you've changed it and it's still giving problems.

[whistle]

Did he check for shorts to earth etc on cable or swap the alarm loop after the 2nd ACT?

[Garry]

Is it a ceiling tile you have mounted it on if so is the tile clipped in if I am mountining 360s I allways mount them on the grid if not possible a peice of wood the same size as the tile and clipped in as this cuts down on the vibration and keeps the NACOSS man happy.

Regards.

Garry.

HAPPY NEW YEAR CHAPS.

[Paul Giles]

Swap the zones, new resistors.

Fit a spike surpressor.

Fit an Aritech DD325, the life saver of false alarms!!

Good Luck!.

Has the Galaxy been properly cabled? EG belden cable?

They should have picked up on low voltage on initial commissioning and fitted a PSU as standard next to the RIO or better still use a SMART PSU!!!

[Guest]

They should have picked up on low voltage on initial commissioning and fitted a PSU as standard next to the RIO or better still use a SMART PSU!!!

Could have been fine on initial install so suspect cabling damaged somewhere since install?

[Guest]

the usual check for ac,earth etc..also check for +v on circ pair causes zone to go open on rios,could change input but would show high/low res in log so doubt its that....im going for + v on circ..

[arfur mo]

i would employ a competant alarm company given your experiences the one you have is not looing too clever :'( - how many visits and still not sorted - very sad story i hope they are not charging for all these calls .

if they are N.A.C.O.S.S. registered and as they (N.A.C.O.S.S.) state in their liturature that the benifits of using a N.A.C.O.S.S. registered installer is that N.A.C.O.S.S. will ensure the alarm company and N.A.C.O.S.S. (not your alarm company) will ensure that ALL the engineers are fully trained, fully competant and fully equiped to install and rectify any fault - thats a N.A.C.O.S.S. declaration that is A N.A.C.O.S.S. promise all that. Hmmmm! thats why i will not DREAM of joining them - GORGI could show them how its done.

if no signs of intrussion, birds, cats or rodents, no reflective or large mobils in range (that scruffy chrome balloon from the office party still bouncing along the ceiling with a deflated contraceptive tied to the string perhaps).

all doors even those not contacted should be checked phisically and either held closed (prefered) so they can not blow open to reduce drafts and control fire spread, or pinned open (not recommended) not allowed them to swing in drafts?

why you ask, because a door moving in front of or away from a heat source can be seen as a movement by both standard PIR and dual-tec. definately.

close ALL the windows shut tight even the little ones, no little vent gaps for 'air' at all. while we are at it, do you have any air bricks near the detector? if so have the detector re-sited.

if you have down pipes or water pipes in range of the detector it can defeat a dual-tec as the water movement during say a storm will trip the micro-wave, if this happens the same time a a draft and both eliments are tripped thus causing the false alarm.

a common way of checking for enviormental broblems is to place a cover over the detector to 'blind' it, if activations are still experienced then it is unlikely to be inviormental (this assums no anti-masking measures are in place).

another approach is to fit a second 'standard' pir detector to a spare zone but put both on test (loss risk allowing) to see if both detectors activate at the same time, if so this will also strongly indicate the enviorment is to blame.

being a workshop do you have any desk fans/fanheaters heatcurtains being left on? - make sure they are all switched off before setting. are any blower assisted heaters operated on a time clock near to the detector? if so check the on/off times against the activation times and best to set for operation outside of the 'set' periods.

there are many other causes of false alarms such as bounced or direct sunlight during high sunspot activity, behing focused directly onto the detector or indirectly reflected of shiny surfaces.

i bet your glad you asked now an alarm service engineers life is so easy - like cutting glass - when you know actually how!

[Guest ALSEC]

a common way of checking for enviormental broblems is to place a cover over the detector to 'blind' it, if activations are still experienced then it is unlikely to be inviormental (this assums no anti-masking measures are in place).

I know this sounds obvious but I've never thought of or seen this done - so simple! You learn something new everyday.