I inherited an existing installation of four smoke/CO detectors. They are all First Alert 3-wire AC-powered units. The test button on each detector produces some weird behaviors:
- Some detectors only sound locally, without producing alarms elsewhere.
- One detector sounds locally and also produces alarms all over the rest of the house (very loud; I can't tell for sure if every detector is sounding).
- One detector doesn't sound locally, but produces alarms elsewhere in the house.
Something is obviously amiss here, and I intend to figure it out. Before I accuse the detectors themselves of being faulty and replace some/all of them (they are only two years old), I want to verify the integrity of the interconnect wire that they all share. Problem is, I can't do a simple continuity check because I don't have multimeter probes (or arms) nearly long enough to stretch across the house.
I'm thinking, after cutting the breaker, of temporarily tying the interconnect wire at one of the detectors to either hot, neutral, or ground and verifying that same continuity exists within all the other detector boxes, but I don't know if that's the best way to go about it.
Anybody have any better ideas for determining if my problem is the detector(s) or the wiring?