Hi all,
Today, I was working on wiring the CO detector in the furnace room in my basement and I ran into a bit of an issue. I was able to give it power via my Silent Knight 5496 power supply and the normal light blinks every so often but when I wore it into a monitor module (SD-500MIM) The entire system goes down. The wires on the module go to the common and N.O. Alarm contacts on the System Sensor CO1224T but immediately after, I get 6 new troubles and the system activates. The monitor module lights up as if the detector activated even though it hasn’t and the troubles say that every device on the SLC in the basement is missing. As soon as I disconnect the module from the detector, the system goes back to normal. Am I wiring something wrong because I’m at a dead end right now. Thanks
When I encounter issues like this, I contact System Sensor directly via email. They are usually very help and are willing to do a call as you are doing the wiring so they can tell you what to do.
[*]Are you certain you haven't mixed up positive and negative SLC wires? That can cause issues like this.
[*]Is the panel programmed to expect normally open CO alarm contacts on the address you have the the SD-500MIM set to?
[*]Do you have a 4.7k ohm end of line resistor installed between the N.O. and common terminals on the CO detector, in addition to the wires to the module? The SD-500MIM requires this.
[*]If so, have you tried putting just the resistor between A and B load terminals on the SD-500MIM, leaving the CO detector off? If the system has all the same issues, this rules out the CO detector as causing them.
[*]If you have a meter, test the N.O. and common contacts on the CO detector. You should read completely open when it is not in alarm.
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A bad SD-500MIM is a possibility if you keep having these issues, especially if it has ever been wired incorrectly. A bad CO detector seems less likely given the symptoms. Let me know if this gets you any closer.
Right now I have the panel programmed for a latching supervisory switch, I’m not quite sure how you program an input module to expect N.O. Contacts if you know how to do this please let me know
UPDATE: I reversed the polarity going to the CO detector and the 7 missing troubles popped up again. Although now I can’t get rid of them. I disconnected the module and usually they go away but they’re still there. Nothing in the basement portion where the module is is polling and will not activate. I checked the programming and according the the manual, the Supervisory switch programming setting for the input module. As quoted by the manual “Use this switch type for tamper monitoring of sprinklers and other fire protection devices. If a contact closes, a sprinkler supervisory event will be generated. Supervisory switches can be latching or non-latching.” which would mean this has to be wired up correctly. At this point I have no idea what’s causing this and I’m now left with a half working system. Anyone with knowledge on this please respond ASAP thanks!
Latching supervisory is fine. A module programmed for supervisory or alarm will return normal condition on seeing an open circuit except for the end of line resistor, alarm or supervisory on a closed circuit, and trouble on a completely open circuit. We almost never use normally closed contacts on fire alarm systems. It sounds like that part is wired fine.
What I would say now is don’t hook this monitor module to your system anymore! Although you have probably come to that conclusion already after your last post. All signs are pointing to it being the cause of the trouble. You may never be able to determine exactly why it is causing the issues, but the first thing I would try is replacing it with a new one. I know it may seem wasteful but these devices fail more often that we’d like to believe.
First, can you tell me where you reversed the polarity? I really don’t recommend trying that on SLC, you could potentially damage your components or panel or both. Also, you say you have missing troubles. Are these devices blinking or showing any indication of being connected to the panel? One thing you can try to see where your problem is is to swap a non-working detector with a working detector. Depending on which one works after you swap them, you can determine whether it’s the actual device that is bad, or something in the wiring from the panel to the device.