A customer's old smoke detector nearly caused a false alarm call out

Last Thursday I was finishing a panel swap in a 1980s house. The existing smoke in the hallway looked fine, but when I tested it, the system logged a trouble signal for a missing device. Turns out the old detector was on a dedicated two-wire loop that the new panel didn't support. The system was trying to poll it and failing. I had to run a new four-wire to a compatible unit. Has anyone else run into this with legacy smoke loops on a retrofit?

3 comments

3 Comments

lane.cameron19d ago

Man, how many hours have I wasted chasing ghosts from those old two-wire loops? Tbh, my first move now is to just assume any smoke from before I was born is gonna give me grief. Last month I spent a whole afternoon thinking I had a bad module, but nope, it was just another ancient detector laughing at me.

alexc9319d ago

Honestly, ever check if the old wiring was even up to code?

-1

holly_walker768d ago

Grab a voltage tester before you even touch the old stuff, seriously. I've seen those old two-wire systems run on some janky low voltage that makes zero sense. Half the time the wiring is fine, but the detector itself is just so old it's reading wrong. Save yourself the headache and test the line first, then swap the unit.