Wired motion sensor started to give false alarms

Reply

  #1  
Old 03-04-16, 07:28 PM
M
Member
Thread Starter
Join Date: Jun 2015
Posts: 12
Received 0 Votes on 0 Posts
Wired motion sensor started to give false alarms

I installed a couple of new wired UTC6540 PIR motion sensors in the basement, they worked fine without any false alarms for about a year and suddenly one of them started to trip. I set it up to give a chime, and it trips every few hours. It seems unrelated to the time of day or the turning on of the heating system.

I am wondering how likely are they to simply go bad or should I look for some non-obvious source of tripping? I already checked that the wiring seems fine and there are no spiders in the sensor.

Mike
 
Sponsored Links
  #2  
Old 03-04-16, 08:17 PM
T
Member
Join Date: Mar 2010
Location: usa
Posts: 603
Received 0 Votes on 0 Posts
if they are in the basement make sure spiders and bugs are not walking across the lens [not just inside].

strap off the zone and listen to see if it might be the board and not the motion.

it has a built-in 3.3k resistor -- is that matched to your system?
 
  #3  
Old 03-04-16, 10:08 PM
C
Member
Join Date: Nov 2009
Location: Maryland, USA
Posts: 1,015
Received 30 Votes on 29 Posts
Have you made ANY changes in the area that the PIR covers? New fixture, aquarium, plant, curtains? All these and more have caused motion falsing.

The usual reason for a PIR to start intermittently falsing is something in the environment tripping it. I'm not familiar with the UTC6540 PIR in particular, but "Pet immune" is a misnomer: They are pet-resistant at best, and can still be tripped by very small animals up close, like a moth fluttering by a few inches away. I would definitely look for possible causes before replacing the PIR.

If you can't find anything, you might invest a few bucks in a low-end PIR like the Honeywell Aurora, replace the 6540, and see if the falsing persists. (Don't throw away the old PIR, it might be perfectly fine.) If the falsing persists, then the problem is almost definitely environmental (including possible critters)

Now temporarily string a 4-wire cable (22/4) across the room and wire both PIRs in parallel, just for testing purposes. Set the Aurora (or whatever PIR you find, but no cheap Chinese junk) so it covers the same area as the 6540 but is positioned at least 10 feet away from your existing PIR.
Now leave it for a day or more and you should have no falsing. Wired in parallel, both PIRs must trip to trigger the zone, which no small critter or hot/cold spot is likely to do. This configuration almost always eliminates the falsing problem.
See if you can find a way to fish the wire so it isn't strung out in the open, and mount both PIRs permanently. You may never find why it falses, but this configuration can solve it.

EDIT: Almost forgot: What make and model is your control panel?
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: