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.

Honeywell 943wg mini magnetic contact

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. Ideally, the sensor and magnet should be in direct contact whenever the door is closed. Please check the installation manual for the sensor for more information on mounting 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 for data transmission. 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. It is also recommended that you use an end of line resistor (EOLR) with these devices so that you 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 to 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 zone is faulted. 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 on test mode with the central station before performing a test.

If all else fails, then it's possible that your sensor may have been damaged. This could be 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 on the door frame, while using the magnet on the door's moving portion. We always recommend using the sensor on the stationary portion of the door so that it is less likely to become damaged when the door is opened or closed. Most door contacts will last a lifetime with proper care, but these devices can easily become damaged if used incorrectly.

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