I am installing my 3rd Alarm.com system and have a problem with several (3 of 12 so far) IQ Mini Sensors (QA1135-840). The sensors install ok with my IQ2 system but then show open when closed. I’ve removed and re-installed, rebooted the panel to no avail. And yes, they work normally right before I install them then after installation show open when closed.
More info - I reinstalled 4 sensors after removing batteries and resetting panel. They all 4 showed as closed then (after about 15 minutes and with no activity on the sensors) they all switched to open.
Can my panel be reset? Other help? I can’t have 4 bad sensors out of 12 purchased.
Where are these sensors being installed? Is the surface they are mounted to made of metal by chance?
Do the sensors report close at all when mounted or just remain open all the time after opening?
How far is the magnet mounted from the sensors on the door/window? Can you post an image of one of the problem sensors in its installed position?
Yes mounted on metal window surround (see photo).
They close the first time they are mounted then they are open all the time after.
Mounted close, less than 1/4 inch.
Thank you for the photo! The magnet looks to be a little misaligned with the sensor in that photo. That combined with the metal is likely going to cause a problem. Re-aligning it may resolve the issue for you by itself.
The reed switch location is at the top of the sensor where the arrow is located on the right side. Basically right at the indented line on the sensor cover. The magnet needs to be more or less centered there. Currently the magnet is mounted below the sensor reed switch on the window.
Basically try moving the magnet up so the top of the magnet is flush with the top of the sensor. Any change?
Yes! That fixed it. The instructions in the box do not say the arrows need to be exactly aligned. Further, the allowable 3/4" gap implies that magnet placement is not so finicky. 
