Entry Door - Sensor Location (ADT Safewatch)


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Old 11-17-05, 06:58 AM
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Entry Door - Sensor Location (ADT Safewatch)

I'm considering replacing my entry door unit, but I cannot find the location for the door sensor. The sliding doors have attached sensors that will trip the alarm, but the front door does not have any visible wires.

I do know that it needs to be open about 5 degrees of arc before the chime will alert me to the door being open. Where are these commonly located? I suppose it could be within the bolt plate. Any advice is appreciated. Hopefully, I will be able to do it myself.
 
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Old 11-17-05, 03:56 PM
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Look carefully at the door frame. Unless they did something odd, there will be a small round spot about 3/8" across. That's the door contact. There will be a matching magnet on the door itself. From your description of the action, it's probably on the header or the hinge side.

You will probably need to get a replacement set. These usually break if you try to pry them out of the hole they are in. When you reconnect the wiring (which will be revealed when you remove the door frame, be sure to use a real crimp type connector. "Twist and tape" is _bad_: you end up tearing your door casing off again to fix the bad connection.
 
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Old 11-17-05, 07:09 PM
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Originally Posted by MrRonFL
Look carefully at the door frame. Unless they did something odd, there will be a small round spot about 3/8" across. That's the door contact. There will be a matching magnet on the door itself. From your description of the action, it's probably on the header or the hinge side.

You will probably need to get a replacement set. These usually break if you try to pry them out of the hole they are in. When you reconnect the wiring (which will be revealed when you remove the door frame, be sure to use a real crimp type connector. "Twist and tape" is _bad_: you end up tearing your door casing off again to fix the bad connection.
OK, it's not like that. There is only a button - much like the operation of a "door" light in a car. There is nothing on the door itself. It is screwed into the jamb in a small diamond-shaped bracket with two small screws. The wiring comes up from underneath the floor and the jamb has been drilled twice - once from underneath for the wiring to the controls, and another (clearly with a spade bit) to mount the bracket. I should get a new button since the one I have could stand to be replaced and it has to be a cheap part.
 
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Old 11-17-05, 07:16 PM
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Oh, ok, you have the old style mechanical switch. In either case, the replacement, of whatever design, will cost less than 10 dollars. The magnetic contacts generally run about 6-7 dollars a set, and the mechanical ones are similar in price. If you don't have a local security hardware dealer that will sell them to you over the counter, they are quite easy to come by from any number of vendors.
 
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Old 11-17-05, 08:23 PM
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Originally Posted by MrRonFL
Oh, ok, you have the old style mechanical switch. In either case, the replacement, of whatever design, will cost less than 10 dollars. The magnetic contacts generally run about 6-7 dollars a set, and the mechanical ones are similar in price. If you don't have a local security hardware dealer that will sell them to you over the counter, they are quite easy to come by from any number of vendors.
Sure looks easy to replace. Do you happen to know of any internet-based vendors that sell these things? I would imagine Radio Shack might have them - possibly even Home Depot or Lowe's. I can't find them on the internet, possibly because I'm not sure what to call them (pressure switch? pressure sensor? push-button switch? push-button sensor? touch?).
 
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Old 11-17-05, 10:01 PM
Roger05
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Replacement switch

When you get a replacement switch, be sure to replace it with one in which the contact is actually a hermetically sealed reed switch that is activated by a magnet attached to the plunger. I never liked to use this time of contact, but sometimes because of the way the door has to be accessed it is necessary. I guess one reason that I didn't like this method is becuase a local alarm co always used the old cheap contacts that were mecanical wiping contacts that would get corroded and would "reliably" give false alarms or eventually never connect back up when closed. He was great for my repair and takeover business, but bad for the alarm industry reputation for false alarms. I'm new here and not sure about calling out a brand name... so I won't. But I believe there is 2 and maybe more brands that use this hermetically sealed reed switch and I know that one of them that I used all the time has terminals with small set screws that make wire connection easy. Also be alert for where the end of line resistor is. It should be somewhere close but not always right at the door. Actually most installers ignorantly put them at the panel. Just be sure you don't cut it out and not put it back or you may never get a closed condition for that door.
 
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Old 11-18-05, 03:44 PM
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Those switches do work well, but I prefer magnetic contacts if the door permits, because sooner or later, the spring on the plunger on those switches gives up the ghost, or the plastic rim gets brittle, and breaks, allowing the guts of the switch to pop out.

Any of the major brands like Amseco, GRI, Sentrol, etc will work just fine. There are lots of online sources. Simply search using the term "security system hardware".

There is no magic bullet for these door contacts. One really works as well as the others. The plunger types do have the advantage of not needing to be precise and align the magnet properly on the door, but have the disadvantage of more moving parts to break. It's a trade-off.
 
 

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