I am thinking I activated the Dual Tec then went outside to wait for
the alarm to stop. It is possible that the DT kept reactivating (like
its predecessor did) due to something that it actually sensed. I
think I need to keep my eye on the LEDs during the initial alarm
Are you familiar with these combo PIR/microwave units. Anything
you can think of that might cause repeated activations? Something in
the house wiring, or outside the house or a reflection? The unit sits
on a running refrigerator next to a microwave oven. The oven is off
but plugged in.
If this sounds suspicious, bear in mind that this never happened
before since these were installed. the location was never changed.
I'll unplug both the fridge and the microwave and try again,
while watching the LEDs.
Any PIRs that you like, minus the microwave?
On Thu, 07 Jun 2012 18:33:38 -0500, G. Morgan
Remember, microwaves will penetrate walls. If the sensor's PIR
part is near a vent it may be the combination of heat change +
something moving that the microwave (radar basically) detects. Any
floating Mylar balloons, any moving apparatus at all in the
Have you tried to adjust the pulse count on the detector? Have
you tried turning the trim-pot down on the microwave field that is
emitted? Have you read the cut-sheet inside and out and
understand how a dual-tech works?
Sure, but a dual-tech is nice for f/a reduction.
Do you have pets that may be setting it off?
The Honeywell Aurora series is a fine brand.
On Jun 7, 9:30 pm, email@example.com wrote:
You think after 25 years it re-wired itself to be backwards?
For the OP, it might be time to consider a new
system. Anything electronic that is approaching 30
years of service is bound to have issues. Just simple
things like electolytic caps for example. Another
problem with a system of that vintage is that it's
probably going to be impossible to program if you
want to change anything, even
if you have the codes. My old one of that vintage
was programmed by blowing PROMS to set the
thing up. You can get a whole new panel kit for
On Fri, 8 Jun 2012 06:41:26 -0700 (PDT), " firstname.lastname@example.org"
Being obtuse again, eh??
The unit was replaced. Always possible the first one was defective and
the new one reversed, no??
Stranger things have happened.
By his description and basic analysis it would APPEAR to be a sensor
related problem - either function or installation, or interference.
I was not talking about the control panel - which appears to be
working just fine, according to the OP's testing. Not saying
replacing it might not be a good idea - but I doubt (not saying I know
it definitely is not) it is the panel at fault.
My thought right now is that he has possibly not removed the jumpers
on the integrated EOL resister pack on the new SENSOR.
That "dynosaur" panel is pretty simple, and pretty reliable. If the
resistance is other than 2.2K ohms or zero (within tolerances) the
panel "faults" and if the resistance is 2.2 K it alarms, and if it is
zero it says "all's well". Basically a voltage devider circuit with a
couple of comparators. If the resistance is too high, the voltage
across the "reference" resistor goes too low. If the resistance of the
string is too low, the voltage across the "reference" resistor goes
high. Either condition trips the comparator
If he has ANY jumpers installed the resistance will not be 2.2 K when
the contacts open. And with the sensor removed and jumpered, the
system will work just fine - as his does.
I believe I made one error on my last post. I believe I said if he had
the sensor jumpered to 2.2K the panel would see 4.4K ohms with the
contacts open. In this setup, it would see 1.1K ohms with the contact
opened, because the resistors would be in PARALLEL, not series.
Hey, I'm not saying NOT to check the resistors - but it APPEARS it
is only the one sensor causing a problem, and if the sensor is removed
from the circuit and a switch substituted, the system works as it is
supposed to. This would lead ME to suspect it is an issue with the
Now,I don't pretend to know it all.
However, many times, particularly with older tech solid state devices,
reverse connections can have strange results, and unlike a simple
switch type "sensor" like a door or window sensor, the microwave and
PIR units ARE polarity sensitive.
On any Honeywell Dual Tec I've seen there is a separate 7-16 (usually
12) volt power supply which is polarity sensitive, as well as the
alarm contacts - which have 4 different programmable resistor values
across the NC contacts if connected C to NC. and another 4 resistors
across the NC tamper switch connections. On some you can connect C to
EOL - I don't know what the rammifications would be if connected C to
Being Normally Closed contacts, if there is more than one sensor or
switch on the loop, they are wired in series, with the EOL resistor
across the terminals at the panel (generally) so with the whole string
closed the resistance across the circuit is nominally ZERO ohms, and
as soon as any contact is opened the panel sees the EOL resistance (in
the OP's case, 2.2K ohms. If the sensor is installed jumpered to 2.2K
ohms, the panel will see 4.4 k ohms with the sensor tripped - and the
panel could "fault".
If he is using an external EOL resistor he needs to remove all of the
If he has not removed the jumpers, it would very likely malfunction
with the sensor connected, and work fine with it removed and replaced
with a switch or jumper.
You can look for zebras and unicorns all day, but when you hear
hoofbeats, it's much smarter to look for horses, ponies, or jack-asses
I've installed a few. Some over 30 years ago, The last ones about 15
years ago - wired and wireless - and I've worked on one of the new
ones within the last 2 years - a whole lot more complex - a whole
computer packed into the box, with complex programming up the ying
yang. Other than moving the control panel (keypad) and a few sensors,
I said "get the alarm company - it'll be cheaper than paying my time
to figure out how to program it".
There's more than just open and closed switches and resistors in the
new digital jobs. The old analog or "2 bit digital" systems WERE
simple. The 30 year old ones were a lot simpler than the 15 year old
ones - which were not "leading edge" at the time.
But (at least most of) the sensors from the 30 year old system still
work on the new systems, and many of the new sensors work on the 30
year old ones as well.
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