Re: pir false alarms

[Matt Ion <soundy106@xxxxxxxxx>]

Jim wrote:
> joble_5@xxxxxxxxxxx wrote:
>
>>Hi,
>>
>>we have an alarm for 2,5 years now. It is a Rokonet system. The PIR
>>detector's used are Pyronix Magnum Ultra.
>>
>>It worked fine for more than 2 years, but last summer we had false
>>alarms almost once per week. Always on the same sensor. Sensor was
>>replaced by the installer, but next night there was again a false
>>alarm.
>>
>>The Pir is now replaced by a dual detector, and this detector seems to
>>work well.
>>
>>The next week we had false alarms with both the two other PIR's. So
>>they are also replaces by dual's.
>>
>>Now it has worked fine for 3 months. But the installer sends us a bill
>>for the replacement of the first detector. And i think another bill for
>>the two others will follow. Together this is the 25% of the price of
>>the system! I do not think this is normal after 2,5 years. (The
>>warranty of the system is 1 year, but on the pyronix site i read the
>>pir detectors come with 5 years of warranty)
>>
>>
>>I want to argue with the installer but first i want to learn more about
>>the problem. So i have some questions:
>>
>>Is it possible that a fly triggers the pir?
>>Can this problem be due to bad adjustment of the pir or the use of the
>>wrong lenses?
>>Can the reason be in the rokonet system instead of in the PIR's?
>>Any other ideas???
>>
>>
>>Thanks in advance...
>
>
> A couple of things that haven't been mentioned yet.
>
> Strong radio frequency signals can sometime cause sensors to trip. Do
> you have any RF souces in your home or do some neighbors?  Taxi cabs,
> police cars etc can sometimes cause problems.

This was along the lines of my first thought: if the original sensor was swapped
out, even with an identical one, and the problem repeated within the same day,
then the problem is clearly not with the sensor itself - there's either a wiring
fault, or the "brain" of the alarm is failing.

I didn't think of RFI, but that would certainly explain the problem occuring in
other sensors/zones.  One test I would have performed as well would have been to
leave the first offending line with NO sensor on it for a couple days to see if
that line triggers again (which of course, would determine or rule a wiring or
brain fault).

> See if you can figure out when ( time of the year) (time of the day)
> false alarms occured. If you've changed window coverings, sometimes the
> angle of the sun at certain times of the year can shine directly into
> motion detectors ..... reflect off of objects in a room ..... heat up
> glass which can rapidly cool ....... or if you've changed houshold
> heating system or moved objects that now allow hot air to flow past the
> PIR's.

Seconded as well.  Unfortunately the OP doesn't mention the relative positions
of the three sensors to each other - are they in different rooms, on different
floors, etc.?  Is this a home, an office area, a warehouse?  More details like
this would help the "remote troubleshooting".

> Obviously, dual technology sensors will help reduce these things from
> affecting sensors.

There is that as well.

Bottom line, from what we're told here, it sounds like the "installer" that put
in the new sensors really didn't do very thorough troubleshooting - the failure
on the other sensors after replacing the first should have been an indication
right away that something else was wrong.  Who knows, maybe the chance to sell
the OP his new "fancy" sensors was incentive not to dig too deeply into the real
cause of the problem.

I hate to agree with Bass here, but I wouldn't pay the installer either - he
hasn't solved the problem, he's just sold the OP snake oil.