urbanscribe said:super helpful as ever
About 2 - smoke detectors --->
You could transfer the smoke detector wiring as-is to the Elk to see if the work. But that seems like a wasted effort, since you will need to replace them anyway with 2-wire smokes. But I would hesitate to advise you on how to connect them in an incorrect manner, even if it is just for test purposes. It will be too tempting to leave them as-is until you get around to replacing them.
let me ask it another way. Why do you think i need to replace the fire detectors. Not necessarily a problem but just want to understand why they should be changed if they connect to DSC now? is it that how it is connected is wrong/dangerous/stupid (saw that above but not sure WHY), or is it that these units may be old enough and cheap enough to change. i'd love to understand better why the FD are wired wrong i guess.
You will need to change the existing smoke detectors because they are 4-wire detectors and are all home run back to the panel. The proper way to wire smoke detectors is in a daisy chain manner so that all the wiring can be monitored for faults. With the home run wiring, the wiring is all in parallel, and a fault in the wiring to any one of them would not be recognized. This creates a life safety hazard, and that hazard is present with the DSC system now.
Some might argue that you still have some protection the way it is, and some protection is better than none. But it doesn't meet code, and in the event of an actual fire, your insurance company may latch onto that as an excuse to deny coverage.
That leaves you with two options.
1. Replace the smoke detectors with 2-wire smokes and re-use the existing wiring. 2-wire smokes on a 4-wire cable will allow you to wire them in a daisy chain manner, even though the cables are home runs.
2. Keep the existing smokes and run new cables to create a proper daisy chain.
urbanscribe said:if i need to change the FDs then:
1. can i use the existing wiring? wireless smokes are > $100 and there are a bunch
2. if i have 10 old ones now then are newer more efficient that they were 5/10 years ago such that i need only 5 (or if i have 10 then i should upgrade/replace 10)
3. should i get 2 wire or 4 wire new fire detectors?
4. any models you recommend
5. do i over complicate things if i look for FD and Monoxide detectors combined?
6. how can i best re-use the existing wiring for FDs. am i right to assume (a) replace all with 2 wires, ( B) connect all the wires to zone 16 on ELK M1 with jumper change?
1. You should be able to use the existing wiring if you reconnect the panel ends to form a daisy chain for 2-wire smokes.
2. I don't know where your smokes are located, but most building codes say you need one in each bedroom, one outside any sleeping areas, and one on each floor.
3. If you want to re-use the existing wiring, you will need 2-wire smokes.
4. For 2-wire smokes, you need to get models that are approved for use with the Elk M1. There is a list in the M1 Manual. System Sensor i3 is one model.
5. It complicates things somewhat to add CO detection, but not too much. System Sensor i4 series COSMO-2W is a good model for this. You'll also need a COSMOD2W module to split out the CO and fire alarm signals. The instructions for the COSMOD2W contain wiring diagrams.
6. See comments above on wiring re-use. If you use the COSMOD2W connected to COSMO-2W detectors, you connect the COSMOD2W to the M1 as if it were a 4-wire smoke detector, so it can actually go on any zone, not just zone 16. But if you use the i3 series, smoke-only 2-wire detectors, then yes, you would connect them to zone 16 with jumper set for 2-wire operation.