Wireless Motion Sensor goes off when A/C set to higher temps

["smsdavis" <smdavis@xxxxxxxxxxxxxxx>]

Ok.  I'm going to apologize.  Although I studied engineering many years
ago, I am NOT interested at all in studying alarm systems and how they
work and I am a woman.  SO, please bear with me but perhaps one of you
geniuses could help me with a problem we have.

Each and every time we leave town we turn our A/C up to about 80 or
possibly higher.  Would have to ask hubby the exact temperature but he
doesn't wish to cool the house while we're gone.

When we do this after we leave town and usually when we're out of cell
phone range our alarm system starts going off.  It is ALWAYS the
wireless motion sensor in our front hall area.

Now, we have a maintenance contract with our provider and they have
sent several people out none of whom seem to know what they are doing
in this area and all of whom have their own theories.

The first one said there was a known problem with that motion sensor
not working properly with our old motherboard.  So he replaced the
entire motherboard of the unit.

We left town and again had to call and have the system ignored while we
were gone as the problem started happening again.

Today someone came out and said he suspects it is the sunlight coming
thorugh the window causing the alarm to go off.  I said if that were
the case then it should be going off even when we're in town and gone
during the day.  He said, no the A/C would cool it down and keep it
from going off.  However, there would stil be a temperature difference
on the stairs regardless of what the AC is set at.

I asked him if there was a specification from the manufacturer with
operating temperatures to which he replied "NO".  As an engineer I
really doubt anyone made an electronic device and did NOT specify
operating temperatures.

So, I'm trying to figure out WHY this keeps occurring.  Is this unit
truly BAD?  Is it the sun?  Is there an operating temperature and
perhaps we need to set the A/C to not go past that limit?

Please, feel free to email me anything that might be helpful to
smdavis@xxxxxxxxxxxxxxx as I really don't have time to check for
answers but I really need to have a reliable system.  Paying for
monitoring when we have to turn off half the sensors in the house is
ridiculous and I don't have much confidence in the techs they keep
sending to my house and from what little I've read it seems you guys
know much more about these sytems than do the techs they keep sending
out.

Thank you so much for anything you can do to shed some light on this
problem.