Help with Ademco 20P door fault


Old 04-17-19, 08:26 AM
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Help with Ademco 20P door fault

I have an Ademco 20P panel which has a simple setup with 2 door contacts, a motion sensor and smoke detector. One of the doors started intermitantly working or showing a fault. I determined the magnetic reed switch was at fault and ordered a new one. While I was waiting I noticed that with the wire ends separated the alarm showed ready to arm.
When I tied the wire ends together, it show a fault at that door???

Shouldn't the circuit be complete(closed) when wires are together??

I got new contact an wired it inplace and now when magnet close to contact it shows door fault and when apart, alarm is ready to program??

I thought maybe I had a short in the wire so I just removed the connection in panel and then put short new wire to panel and alarm contact but it does the same thing??

Any thoughts?
Old 04-17-19, 02:20 PM
Join Date: Oct 2009
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Sounds like the contact is programmed into the system as an NO (normally open), and your old contact probably had both a set of NO and NC terminals, and the wires were hooked up to the NO terminals. Change the zone type to NC and you should be ok.

Wired zones can be programmed as NO, NC, or EOL (plus a couple of rarely used options).
Old 04-17-19, 08:46 PM
Join Date: Nov 2009
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Before you change programming, check to see that your zones are landed on the right terminals in the control. It can be really easy to get a zone loop offset and connected to the adjacent zone. This is especially easy for Zones 2 & 3, and Zones 3&4, if you overlook that Z2 terminals 8 & 9 are dedicated to one zone but 3 & 4 terminals 10, 11, & 12 share a common ground (T11).
But you can get a zone loop offset in any zone, with all those wires next to each other.
Old 04-18-19, 11:24 AM
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Thanks for these suggestions. I will check these out and report back!

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