Two ways:

one, simply cause an alarm at one detector and have a helper stand
under one elsewhere in the house.

two, pull one down and see how many wires are hooked up to it. If it's
only white and black, they are 120VAC but not hooked up in tandem. If
there's also a red wire in the box, they are likely tandemed. The
terminals ought to be labeled, so you can also tell that way. Make
sure to cut the power if you don't have confidence that you can do this
without touching any of the terminals. If you think you might want to
cut the power, you want to cut the power. better safe than sorry.

good luck,

nate

Myrna wrote:
Hi, Tim,

Thank you to you and everyone else for your answers and guidance.

I have no idea if my 3 detectors are wired together. When the one in
the kitchen sounds (if I broil, it always does), I have no idea if the
others are also sounding. Is there any way to tell this? Over the
years, we have found many areas where the builder and his workers cut
corners. I would not be surprised if this is yet another of those
areas.

Myrna





AlarmArm wrote:
Hello Myrna,

All 3 should be replaced bacause of their age. As with all electronic
devices, smoke alarms degrade over time, and the failure rate increases
over time. Most manufacturers indicate that smoke alarms should be
replaced every ten years.



Best regards,

Tim