The Honeywell 947-75T is a recessed door contact designed specifically for steel doors. Normally recessed door contacts cannot be used in steel doors because the steel door interferes with the magnet. However, the 947-75T magnet is much larger and therefore will work reliably even when installed inside a steel door. You can choose between a white contact (947-75TWH) or a brown contact (947-75TBR).
Just like the Honeywell 944TSP recessed contact, the 947-75T uses screw terminals to connect the contact to a wired zone on your alarm control panel. In fact, the 947-75T uses Honeywell’s exclusive Staggered “T” terminal screws which make installation much easier. Honeywell came up with the staggered terminal design so that the screw terminals could be larger so that you don’t need to fumble with tiny sized terminals. The larger terminals make it easier to connect your zone wiring connection and fit standard sized screwdrivers. You could also use Honeywell 947-75 steel door recessed contacts, but it is much easier to install recessed contacts with terminals than it is to install recessed contact with leads. Using terminals eliminates the need to splice, solder and tape the wiring connections.
The Honeywell 947-75T steel door recessed contact utilizes a Form A, SPST, normally closed internal reed switch which has a rating of 100mA at 24VDC. When the corresponding magnet energizes the contact, the contact loop is closed and the alarm control panel is happy. If the steel door opens, the magnet is pulled away from the 947-75T and the contact loop opens which triggers an alarm. To keep the contact loop closed, you must ensure that the magnet is not further than 1/2” from the contact when the steel door is closed.
To install your 947-75T steel door recessed contact, you will need to drill a hole with a 3/4” diameter into the outside edge of your steel door and a corresponding 3/4” diameter hole into your steel door frame. You can also choose to drill the hole into the top edge of the door so that no one will see the magnet when the door is open. After drilling your holes, you must run a (2) conductor alarm wire from your alarm control panel to the hole in your steel door. First, connect your alarm wire to the (2) screw terminals at the end of the 947-75T recessed contact. Then, press the recessed contact into the hole in the steel door frame so that the end cap is flush with the edge of the door. Complete the installation by pressing the magnet into the corresponding hole in the steel door. When you are done, the magnet should be directly across from the contact when the steel door is shut. To avoid misaligning your Honeywell 947-75T steel door recessed contact and magnet, we suggest marking your holes before drilling.