I recently changed my back door in my house and now the alarm will not work. I had a wood door and replaced it with a metal door. The original door had the magnet plug in the door which matched up with a sensor. However, I tried to do this with the metal door and it does not work. I can place the magnet plug up to the sensor and it works. However, when I place the plug in the door it does not work. I assume it is because it is getting demagnetized in the door. I called ADT, my alarm company, and they said it would be about $150 do change the sensor. I was wondering if there was something else I could do that would be a DIY and not cost the money.

Thanks for any information.

 

Some of it is the precision of your alignment. This type of contact doesn't have a lot of lateral tolerance (you can't be off center more than 1/3 the width of the magnet), and the gap cannot be much more than a half inch. I ususlly spend a bit of time carefully measuring this type of door before I drill the hole. Metal doors complicate matters a bit more, as the steel can distort the magnetic field. The normal solution, is a plastic plug that surrounds the magnet with a ring of plastic, keeping it away from the metal of the door.

If this is the type of door that's a metal shell over foam, that's your only real solution. There are two styles. One is a press fit that fits into a 1/2" or 3/4' inch hold, the other has a flange that has a couple of screw loops. It sticks out above the surface of the door cap a little, and is actually a better choice if the problem is a big gap between the top of the door and the header rail.

If the gap between door and header is pretty big, another option is a thin "rare earth" magnet that can be glued or screwed to the surface of the top edge of the door.

 

It is aligned fine as I checked this carefully as you suggest. The gap is about 1/4 inch so do not see that being a problem. Can you suggest where to get these sleves? The only problem is that I drilled the whole in the door fairly tight so unsure if I can get it out.

Also, where to you get these rare earth magnets. I tried a couple of refrigerator magnets and had no luck.

Thanks for the assistance.

 

Here, try these guys. They have the hardware bits and pieces you are looking for. Pretty much any security hardware dealer will likely sell you these over the counter.