Monitor independent smoke alarms with DSC PC1832?


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Old 05-05-21, 08:46 AM
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Monitor independent smoke alarms with DSC PC1832?

New member. Novice. 1st post. Looking for advice / guidance.
I replaced a CADDX panel with a DSC PC1832 set for no EOL resister, NC zones.
Door and motion sensors are the originals and the zones are working as expected.

Question:
The house also has 5 independent smoke alarms (KIDDE) that are interconnected. In addition, there is a relay, with two wire output that was monitored by the CADDX panel. The relay is NO.
Is there a way to allow the smoke relay to be monitored by the DSC panel as a Fire zone, given than the panel is programmed for NC zones and no resistor?
 
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Old 05-05-21, 09:44 AM
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Welcome to the forums.

In order to use an interconnected smoke detector system relay the panel needs to be programmed for a normally open and supervised point with eol resistor. You can reprogram a single point as needed.


On edit:
FYI.... the interconnected smoke detectors will not trip an alarm panel during a power outage.
The interconnect relay uses 120v in its operation.
 
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Last edited by PJmax; 05-05-21 at 10:23 AM.
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Old 05-05-21, 12:02 PM
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PJmax Thank you for your quick response. That is welcome news.
Is the reprogramming done in Section 108 (for zone 8).? Are there other steps I should take, such as disabling the zone before changing its characteristics? Will the panel then identify the new zone automatically when the zone is enabled again?

Yes, I understand the interconnect relay is line powered, but that would be a rude surprise to the unwary! We have a backup generator, so I'm counting on any power outages being brief. (It's been like that for over 15 years with the CADDX panel.)

Mike
 
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Old 05-05-21, 03:40 PM
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With DSC (if memory serves), even if the option for the zones to be NC is set, if you set a zone input e as a hardwired fire zone, it looks for the NO with the end of line resistor for that specific zone.
 
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Old 05-05-21, 05:00 PM
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Exactly as MrRonFL said, when panel is programmed for Fire zone, it becames a Normally Open zone and needs 2.2k or 5.6k Ohm resistor (can't remember which one).
 
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Old 05-05-21, 05:07 PM
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That's even easier. I'll definitely give that approach a try first. Might even leave time for a
Thanks.

Mike
 
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Old 05-05-21, 05:18 PM
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It's going to be 2.2k ohms.
5.6k is the secondary point function which will not be active on a fire point.
 
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Old 05-05-21, 05:25 PM
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It's going to be 2.2k ohms.
5.6k is the secondary point function which will not be active on a fire point.
I just looked at installer manual, it says 2.2k EOLR for 2-wire smoke and 5.6k EOLR for 4-wire (as used in this case). But I also think that it's going to be 2.2k for all fire related zones, but said just in case if it doesnt work with 2.2k resistor, try with 5.6k. DSC manuals are known to have some wrong informations in it, and they never change it when updating manual or making new model. And resistor should be connected in parallel at the farthest smoke detector location.
 
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Old 05-06-21, 07:48 AM
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From the 1832 V4.6 installer manual under Trouble 5 Zone Fault: "Ensure fire zones have a 5.6K resistor (Green, Blue, Red) connected"

Do the relays in ALL the smoke alarms close when ANY smoke alarm activates?
 
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Old 05-06-21, 09:44 AM
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As far as I know.... there are no relays in the smoke detectors. They send out either a set voltage or data pulse on the red wire that each detector sees and audibly acknowledges. The only relay is in the connection module.
 
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Old 05-06-21, 03:38 PM
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In a 4 wire smoke, the alarm contact is a dry contact relay. Only the active smoke switches it's relay.
 
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Old 05-07-21, 06:35 AM
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OP specified "interconnected" so I'm reading smoke alarms, not system smokes. His backdoor route has pitfalls and he appears to have tunnelvision. I've experienced tunnelvision plenty of times.
 
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Old 05-07-21, 02:48 PM
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Ah, quite right. I totally forgot that this was an interconnect relay situation (which I typically discourage).

The individual smoke alarms will trigger the sounder on all smokes on the interconnect loop; assuming that they are all the same brand and model series. Gentex, and Firex/First Alert, for example, are not inter-compatible, for example.
 
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Old 05-08-21, 06:40 AM
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OP specified "interconnected" so I'm reading smoke alarms, not system smokes. His backdoor route has pitfalls and he appears to have tunnelvision. I've experienced tunnelvision plenty of times.
The smoke detectors are smoke alarms. They are not integrated with the alarm panel, just report alarm status via a relay.. Not sure what you mean by "tunnelvision".
 
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Old 05-08-21, 06:55 AM
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It was (in my opinion) inelegantly worded; but the point that ThisOldMan was making was that connecting consumer grade smoke alarms to an alarm system is generally not recommended for a number of reasons.

You do, however, seem to wish to do so, so we will give you the advice you need to do so with the least likely hood of major issues.
 
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Old 05-08-21, 06:04 PM
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I'm a novice, but willing to learn. I may not have asked the right questions. I'd love to know what the reasons are for not connecting consumer smoke alarms to a security system. Does it increase the risk in some way? I assume the smoke alarms will continue to work as designed and notifying the alarm system would be an added benefit. What am I missing?

For context, it may be worth noting that the smoke alarms were installed (almost 20 years ago) independent of the CADDX alarm system. The relay was added later. The smoke alarms have been replaced due to age, but using the original wiring. They are tested periodically, and appear to function as intended. I am now replacing the CADDX panel with a DSC panel. Door and motion sensors have not been touched.
 
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Old 05-08-21, 06:58 PM
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It's not something supported by fire prevention codes or UL listing (which means that it's problematic for insurance company indemnification). Additionally the manufacturers specifically say you shouldn't because it's an unsupervised connection that doesn't function in the instance of AC power failure.

"CAUTION: The model SM120X should not be used to connect groups of alarms to a fire alarm panel or to interconnect groups of fire alarms together."
https://www.shareddocs.com/hvac/docs...erGuide_EN.pdf

A lot of life safety design (and codes) revolves around avoiding creating an "illusion of safety"; so as long as you recognize that this connection is, at most, supplemental, and not to be relied on, there's no _law_ against it.
 
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Old 05-09-21, 06:44 AM
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Thank you for the additional information.
I'm confused about one thing. The interconnected smoke alarms were originally installed as they were explicitly to comply with code requirements. (That did not include the relay to the alarm panel.) Are you saying that by connecting the smoke alarms to the panel, I am now in violation of code? Even though the connection has no effect on the smoke alarm function and they continue to perform as intended?

Just to be clear. The alarm panel is not a fire alarm panel. It is a general purpose DIY alarm panel. (That's what this forum is about, right?) Further, none of the zones are supervised in any way (no EOL resistors). It's intended as an additional layer of information and notification, not as a life safety device.

The smoke alarms are intended to be life safety devices, however. I expect them to warn the occupants in the event of smoke and to do so in a way that gives them the opportunity to exit safely 24 hours a day. I do not believe that adding the relay and connecting its output to a DIY panel affects that function, but if it does, I won't connect the smoke alarms to the panel.
 
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Old 05-09-21, 07:29 AM
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It is an intrusion alarm panel that is UL listed to support 2-wire and 4-wire smoke detectors. This configuration is outside of it's UL listing.

Single station, interconnected smoke alarm (note the difference in descriptor) have their own separate section of NFPA 72 (the fire alarm code reference). Those are what are required as minimum building/fire code standards in most jurisdictions.

Connecting the relay to the intrusion alarm doesn't impede the function of the smoke alarms; it's simply outside the scope of what the device is UL listed as an application. Again, you would not be in violation of any specific code, nor is it impeding functionality; just understand that it is not a reliable configuration.


 
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Old 05-09-21, 02:52 PM
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Thank you for sticking with me on this. I definitely appreciate the clarity you've provided.
I'm a bit puzzled by the concerns expressed, but I can understand the need to clearly distinguish that amateur jobs like mine are not UL compliant configurations.

That said, it would have been less confusing to me if the answers were more explicit about safety and utility.without vague "not recommended" comments. If nothing I'm doing is likely to make my fire alert system work less reliably than it otherwise would, why not just note that it's unlikely to make the system safer, but also unlikely to degrade performance either?

If there is concern that complying with minimum building codes is insufficient, saying so explicitly - and explaining why - would be useful.
If there is concern that I may be unaware of relevant options, a link to more information would be useful.
In the end I feel like I had to work harder than I should have to tease out what it was about my question that was concerning. (And to be honest, I'm still not sure I fully understand.)
 
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Old 05-09-21, 03:28 PM
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Specifics of building codes vary widely by jurisdiction, and DIY work like this rarely gets AHJ scrutiny; so it's not normally productive to be too specific. Nearly all of this information is referenced in the installation manuals and data sheets for the products.

Even though your specific question is being addressed, the information in these thread remains for other people to reference.
 
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Old 05-10-21, 10:13 AM
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Nearly all of this information is referenced in the installation manuals and data sheets for the products.
I'm sure that's true, but the DSC installation manual is not organized for a novice, and the information I was looking for was not clearly spelled out. That's why I came here. I was hoping to find more experienced and knowledgeable users who could help me sort out what I was looking for.,

It's also of interest that one of the early responses was:
DSC manuals are known to have some wrong informations in it, and they never change it when updating manual or making new model.
In fact, I believe I did get clear guidance concerning my question. What threw me were some vague statements that implied that what I was doing wasn't well thought out at best and possibly dangerous at worst. Trying to follow up on those to understand the nature of the concerns was what was the difficult part.
 
 

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