sm-120x and sk-4?

We had a new furnace put in today, and the installers also wired a 4-wire smoke/co combo detector. I can’t recall the exact model off-hand, but it’s a Kidde. The manual lists that you can get a relay for it… the sm-120x.

Sometime during this spring or summer, I’m planning on getting and installing a fire alarm system using an sk-4. Doing some research and manual reading, this is what I found so far:

  • The sm-120x manual states that it’s not recommended to connect into a panel with multiple-alarms, since the detector itself is non-latching. My question is this. That would be the only non-latching detctor in that zone. Am I correct in interpreting this as more of an advisory against hooking it into a panel with multiple non-latching detectors, as opposed to it being a concern about harming the module/panel?

  • The detector itself gets its power from the breaker. Town code where I am states that rooms with a boiler must have a hardwired detector straight into the breaker. The relay module would also be on this circuit.

  • The detector has one communicator wire, which would go into the relay module. The relay module would go into the zone with the pull stations/i3 detectors.

  • Power supply has to be 120V for the detector and relay. So running it off of panel power is out of the question.

My questions:

  • Are there any alternative relays that would work for this that you guys would recommend over the sm-120x?
  • If I replace that with an i3 detector and get a dedicated CO detector… would hard-wiring the panel into its own circuit and running the detector off of panel power satisfy the town code requirement?

Home Page for Carrier air conditioning, heating, refrigeration and HVACR service(25.pdf

^ Manuals I looked through

Apparently can’t edit posts, but I wrote that at 5AM this morning and forgot to include the “disclaimer” - so sorry for the double post.

Wiring the detector relay would be the only “life-safety” aspect of the system. Everything else, despite it running through the entire house, would be hobbyist, and installed either alongside battery smoke detectors, or using brand new detectors straight from a distributor/the manufacturer. Also, the CO alarm has a built-in battery backup and again, is wired stand-alone into the circuit breaker. The relay would be what connects to the system. In the event of a relay failure/system failure, the detector itself would still work and go off. The main reason I’d want to wire it in would be so that we can hear a horn going off upstairs should it go off.

The more I think about this though, the more I’m thinking might just say screw it and replace it with an i3 smoke, and get a dedicated CO detector in a separate location further away from the furnace than the one that they installed is in order to satisfy the hard-wired CO Detector town requirement. I don’t like that the detector doesn’t display PPM on it, and that its threshold for even going off/activating is relatively high. And just to clarify, the requirement is explicit to CO Detectors. There’s no codes for requiring smoke detectors being hardwired in a house in my town.

Anyone got any ideas on this? I keep going back and forth on what I want to do with it, as far as just replacing the detector completely. irregardless, I’m gonna get one with a PPM counter on it, but I don’t know if I want to go all out and replace this one just yet.