ELK M1 and 2-wire smoke detectors


Active Member
Well I think I have a big problem and thought I'd ask for advice. I'm planning for my transition to my M1 gold system and making sure I have all the necessary parts - boards, mounting stuff, resistors, jacks, etc. And making the check list and step by step plan.

And now I find the big problem - my current house has 14 smoke detectors - 6 on the 2nd floor, 5 on the main floor, and 3 in the finished part of the basement. Plus 8 heat detectors - 3 in the garage, 1 in the attic storage over the garage, 1 in the attic storage over the second floor, 1 in the furnace room, and 2 in the basement.

These are hooked up in a daisy chain fashion and wired into 3 zones!!!

I'm not sure if the heat detectors are chained in with the smoke detectors or not.

But, basically it looks like I'm screwed since the M1 wants all the 2-wire smokes on zone-16 and limits them to 20 plus requires EOL resistors, etc. So it looks like I have alot of work to do which is why I'm seeking advice. (Elk guys: why doesn't each 16-zone expansion module let you hook up 2-wire smokes to relative zone-16 on the XIN board?! )

I haven't examined any of the detectors yet. I'm not sure how to remove them from the mounting plates AND I'm not sure if that will set off the alarm.

And I'm not sure how to tell which ones are wired together - I'm sure I can make assumptions, like all the upstairs ones are wired together, but that's just a guess.

If you go to the panel and disconnect a zone it should go into trouble but not alarm. You can then tell which detectors are on that zone by observing the flashing LEDs on the detectors. (The ones no longer flashing are on that zone).
Check the panel that you have. It might also only support 2 wire smokes on one zone. If you dont have the documentation for the panel ask on here. I can get most ADT, Honeywell Ademco, and Napco documentation.

It may not be as bad as you think.
It's a Eurorplex 3GS and I can't find anywhere in the documenation where it talks about smoke detectors, let alone 2 verus 4 wire issues or EOL issues with smokes. It does requires EOL resistors for ALL zones - which the installer just put in at the panel - I guess his definition of EOL was different then mine.
The Europlex website seems to have documents you can download. For whatever reason I cant get them at the moment (says it transferring teh document but nothing happens).

I am not familiar with this company at all but hopefully someone else is.

I will try again in a little while
And the other reason I beleive they are two-wire smoke detectors is that the red jacketed wires only contain a red and black wire for a total of 2 wires. And they are wired to zones 1, 2 and 3.
Put the two wire detectors on zone 16 and the heat detectors on any other zone defined as 4 wire smoke detectors with a 2200 ohm end of line resistor.

The 3 zones of 2 wire detectors will have to be daisy chained into one zone to work correctly.
Daisy chaining them together is my problem. While the 6 smokes on the top floor should be attic accessable, none of the others is, so there is no easy way to daisy chain them without ripping up sheetrock, which I'm not really excited about. Who knows, maybe I'll get lucky and the hard to get to ones will be already in a single daisy chain. Then again, maybe I'll win the lottery.

So there's no magic hardware device that would interface to each of my detector strings, then let me run the magic device into any old input zone?
If the top floor are accesible cant you run a line from there back to the panel and out to the second string of 2 wire smokes as Spanky suggested? If all of the 2 wire detectors are on 2 zones this should work. Then the heat detectors can be on any zone configured as a fire zone.
Yes, that was my thinking as well. My fear (maybe my hope) is that what they did was run 3 loops - basement, first floor, second floor. If that's the case, I can chain the first floor and the second floor together and rip out sheet rock (gag) in the basement ceiling.

Question, how do you take the cover off of a smoke detector? I've been on the ladder looking at one, but it's not obvious to me. No model numbers, etc on the outside - just "do not paint" lettering molded into the plastic.
Usually you have to gently twist them to the left. Some have a little tab. Depends on the brand/model.

Dont be alarmed (ok bad pun) if you get a trouble on your system when you pop a detector. In fact it had better go into trouble. If it doesnt then it was not wired properly.

You can also see what zone each detector is on by looking at the keypad to determine which zone is in trouble.
Okay, I'm an idiot. The 2-wire red jacket connectors go to the speakers and sirens. There's another set of 4-wire red jacket connectors (green/white/black/red) going to the zone inputs. These were hidden behind the 2 batteries that sit in the bottom of the can. And I finally was able to get the cover off an detector (the 3rd one I tried, they are really on tight) and verified it. The are ESL model 541C.

There is no EOL supervison relay in the panel, but it appears the cables are run in a loop - 6 cables, with 3 pairs having similar names (2 called up-loop for example). One of the up-loop wires is connected to the panel (zone 8) and red/black going to power. The other up-loop wire has the green and white wires tied together with a resistor and the red and black wires are not connected, just terminated.

Which leads to 2 questions:
1. Is there a simple way to tell if theres a supervision relay in the circuit?

2. Is there any problem with heat detectors diasy chained in along with the smoke detectors (they are AIP AI128B)?
I could be wrong, but I do not think you are supposed to chain heat detectors with smokes (I think it is only supposed to be the same model two wire smokes on the zone). I did my setup with 2 wire smoke detectors on zone 16 and then three other zones for heat detectors ranging from one to three detectors in each zone.
It is beginning to sound like you have 4 wire smoke detectors instead of 2 wire detectors. If so, there is not a problem with stringing the heat detectors along with the smoke detectors. An end of line power supervision relay would normally open the EOL resistor supervised fire loop if power fails to the end on line relay module.

541C is a 4 wire smoke detector.