Troubleshooting false alarms on Fire Zone

I have an OmniPro II and the Kiddie SM120X relay connected to my 120v existing smoke detectors.
 
The setup seems to work fine and triggers properly when any of the interconnected smokes are tripped. However, twice in the past 2 years (including last night at 3AM, of course), the Fire Zone has tripped with what seems to be no activity from the smoke detectors. That is, the alarm panel triggers it's fire alarm but the smoke detectors are NOT in any alarm state. During this time there was no fire, no power loss or spikes of any kind, and nothing that I can discern that would cause the relay to close.
 
The SM120X is wired using the NO contact with a 1k ohm resistor in parallel at the relay. The OmniPro shows the loop value of this zone at about 145-146 most of the time, which is consistent with the other zones on my Expander Board (all of the expander zones live in the 145-146 range for loops while the non-expander zones are usually in the 148-150 range....not really sure why).
 
I'm using Zone 17 (EX-1 on the expander) set as type "Fire Emergency".
 
Any ideas why this would randomly trip an alarm? Is it ok to have a Fire type zone on the Expander? Should it be "Fire" or "Fire Emergency"? 
 
NOTE: I'm aware of and respect the disagreement for the application of this relay for monitoring of this type. For me, my panel is not monitored so I believe this application augments the fire protection and does not replace it.

longwa said:

I have an OmniPro II and the Kiddie SM120X relay connected to my 120v existing smoke detectors.
 
Any ideas why this would randomly trip an alarm? Is it ok to have a Fire type zone on the Expander? Should it be "Fire" or "Fire Emergency"? 
 
NOTE: I'm aware of and respect the disagreement for the application of this relay for monitoring of this type. For me, my panel is not monitored so I believe this application augments the fire protection and does not replace it.

Click to expand...

I have this truck that that wasn't designed to pull a trailer, but when I do tow a trailer, and only off-road, the brakes overheat. Can you tell me why?  I'm not driving it on any public streets so it should be fine.
 
There really isn't much disagreement. You do things correctly or you don't.  You know your are not doing it correctly, but then you want us to tell you why it doesn't work? 

Your analogy is flawed. It would be more like saying: "every time I drive my truck on the wrong side of the road, the engine breaks down". See, those are two different things and while one is not allowed by law (code) it should not inherently affect the operation of the engine (or system in my case). I'm not sure why you seem to have such a difficult time understanding the difference.
 
At any rate, I know why it's not "correct" from a code/UL standpoint but those reasons don't seem to be the same reasons that I'm getting the false alarm. For instance, there were no power outages or spikes during the time so lack of AC power isn't a concern. The smokes did not activate in any way so it's not a false alarm problem caused by crappy ionization type smokes.
 
Do you have anything constructive to add?

These kinds of nuisance alarms are a pain, ignoring the above argument, it sounds like the usual intermittent problems.  Interconnect wiring first and then failure of some unit in the system.  Bad connections are the number one cause of system problems and can be hard to identify (especially when only rarely intermittent like in this case.)
 
How old are the 120V smokes and the SM120X?  I was not familiar with that unit, but the install instructions have a couple of limitations that surprised me.  For example, they recommend the entire install (smoke - SM120X - attached equipment) be on the same circuit branch.  They also say no use of non-sine wave AC power.  Do you use any backup power in these circuits?
 
You may just have a marginal or failing SM120X or attached smoke detector (or Omni zone input, I suppose.)

cobra said:

For example, they recommend the entire install (smoke - SM120X - attached equipment) be on the same circuit branch.  They also say no use of non-sine wave AC power.  Do you use any backup power in these circuits?

Click to expand...

This is a requirement of ALL interconnected smokes. Check the building codes. This is all spelled out.

ano said:

This is a requirement of ALL interconnected smokes. Check the building codes. This is all spelled out.

Click to expand...

Well, my understanding was he had a 120V smoke system, and this is secondary for monitoring.  I would expect the wired smokes to satisfy the building codes.  Couldn't the SM120X be additional to the code requirement?
 
The question would be is the other side of the SM120X also on the same circuit?

Especially read this line:
Caution: The SM120X should not be used to connect groups of alarms to a fire alarm panel... 
 
it IS designed to connect auxiliary warning devices such as bells, sirens, hallway lighting, stairway lighting. 
 
So what is the difference, you may ask.  Devices like bells and sirens and hallway lighting only operate if the 120V source is present. But with an ELK, OMNI, or other fire panel, that isn't the case. Power spikes and power outages on the 120V circuit can likely cause false or missed alarms on the Omni or ELK.  Also what happens when your 120V goes out like it can during a fire? The SM120X would not work, so you don't get an alarm.  Do you really want to rely on a smoke alarm that may not work during a fire? 
 
The correct way to do it is only use 12V smoke alarms on your panel that were designed to work with your panel AND keep all the 120V smokes to meet building codes but don't connect the two together because each was designed for a different purpose.  As you see, when you disregard that you could have false alarms.  Maybe worse is the opposite problem, when you really have a fire will it all work?  Id stick to what is known to be proven and tested.

Ano,
 
The reasons you state for a case to NOT connect are true, however you're missing the point of why the SM120X is not intended for connection. It's not listed for the purpose. End of story.
 
It's "harmless" as far as the panel is concerned, if the coil doesn't fire, so be it, it's not going to damage the panel, only prevent notification.
 
It's allowable to be installed by code, NEC and NFPA, however the connection to a listed FACP for notification purposes technically isn't (grey area).

The main reason why is the listing, which entails the details of why it's unlisted......there's no way to supervise the opposite side of the relay coil for proper operation, which is mandated.
 
I would guess there's probably a ground fault or similar going on, even the unit's 9V interconnect. Relays don't just fire.

I was planning on connecting a SM120X relay to my Omni panel.  I have been reading multiple posts related to this today and have learned some things, but also raised some questions.  I never knew this was such a hostile topic, but I am glad that I looked into it.  So that I may better understand the issues at hand, can I ask a few questions?
 
I have read about the reasons for having either standalone 120V smoke detectors, or 12V (or 9V) dc smoke detectors that are intended to be installed into a FACP.  I understand that, at least to some extent, it may have to do with the fact that if the 120VAC power is lost during a fire, the relay will not close, and therefore my alarm panel would not alarm.  Whereas with a dc smoke detector powered off of the alarm panel (which has battery backup), that power would remain intact.
 
My question, which I've seen people ask, but never seen a clear answer is this:
 
To the best of my knowledge, it is an approved installation for me to have 120VAC interconnected smoke detectors that have 9V batteries as backup.  When any individual smoke detector alarms, they all go off.  That is my primary notification that there is a fire, and that is what will alert me to wake up and get out of the house.  If I were to add a SM120X relay to the system and connect it to my alarm panel, does that in any way affect the functionality of the smoke detectors and/or prevent them from alarming in the event of a fire?  In my mind, that should still function like it always did.  The "local" alarm that each detector provides would still remain in place, the SM120X relay is just an "extra" notification sent to my alarm panel.  If I were to lose 120VAC power during a fire, I understand my alarm panel would not sound the siren, but I'm not relying on that to alert me anyway.
 
I'm just trying to understand what safety hazards, if any, the addition of the SM120X causes, other than its just not what it is intended for.

The official standpoint is the device is not listed for the purpose, so in actuality, it has not been tested by NFPA or UL to be suitable for the purposes intended, which can be interpreted as it hasn't been determined if the relay causes harm or interference with a downstream connected system or not.

In theory, it should do no harm to the connected system assuming the relay coil is isolated from the dry contacts properly, but nobody has tested it to verify, hence the "no listing" on the device.
 
Dropping out of the discussion and fray on this. Really don't like the idea of doing this on many levels.

I think DEL is spot on with what he says.  From a strict technical point of view, there might be no problem in doing this.  But there also could be a unforeseen problem and no one has tested it to figure out what that might be.
 
Overall, you could be opening yourself up to legal issues more than anything.  Using components that are not listed for the purpose gives your insurance company a possible reason to not pay for damages from a fire, especially if you were getting a discount for having a monitored fire alarm system.