Why Does the Wired Alarm Contact on My Door Not Work?

There are many possible reasons why the wired alarm contact on your door does not work. The main factors to consider are how the sensor was mounted, how the sensor was wired, and how the sensor was programmed. It's also possible that the sensor was damaged and needs to be replaced.

The first thing to check with a wired alarm contact is its mounting position. A contact sensor consists of two (2) main parts. These parts are the sensor and the magnet. The sensor should be mounted on the door frame, while the magnet should be mounted on the door's moving portion. When the door is closed, the sensor and magnet must be in very close proximity. The maximum allowed magnet spacing gap varies between different sensors, but it is usually around half an inch. Having the sensor and magnet too far apart will prevent the system from showing that the door is closed. You must make sure that the sensor and magnet are properly aligned and that they are not spaced too far apart when the door is closed. Ideally, the sensor and magnet should be in almost direct contact whenever the door is closed. Please check the installation manual of the sensor for more information on mounting and gap guidelines.

Next, you must make sure the sensor is wired properly. This includes the wiring at the panel and at the sensor itself. Although these sensors do not draw any power from the panel, they must still maintain a proper connection in order for the alarm panel to know the current status of the door. There will normally be two (2) wires going from the sensor to one of the hardwired zones on the panel. Make sure that these connections are nice and secure. You should also make sure that these cables are not cut and that the connection between the sensor and the panel is not broken. It is also recommended that you use an end-of-line resistor (EOLR) with these devices so that your system knows if anyone has disabled or tampered with these sensors.

If the mounting position and the wiring both seem okay, then the next thing you will want to check is the programming. Hardwired contacts need to be programmed into a system zone. This tells the system how to respond when the door is opened. If the programming settings are not correct, then the system will not respond in the correct manner. It's also possible that the sensor was never programmed with the system. Another possibility is that the zone programming was accidentally deleted. If that is the case, the system will not respond at all when the door is opened. Make sure that the programming is correct, and perform a test to make sure that the system responds correctly when the sensor is activated. Remember to put your system in test mode with the central station before performing any type of alarm test.

If all else fails, then it's possible that your sensor may have been damaged. This could be due to a hard blow to the sensor, dropping the sensor from a high location, or using the sensor in any manner that is discouraged in the installation manual. You can prevent damage to a contact sensor by installing the sensor properly on the door frame and making sure that it is mounted in such a way that it won't come loose or fall off. Most door contacts will last a lifetime with proper care, but these devices can easily become damaged if used incorrectly.