We appreciate your reply. We honestly didn't know what to do, and couldn't find directions on the Internet or even an old manual for that unit.

Those old model smoke detectors are of No use anyway because if fire got anywhere near wiring the breaker switch will cut off, secondly we need to replace smoke detectors after 10 years to make sure it will function. So just replace with a modern Smoke detectors for your safety.

I'd guess that Agrandma probably solved her smoke detector (or is that Smoke detectors?) problem a long time ago. This thread is from 2010. AFAICT, she hasn't been back to Gardenweb since.

Shouldn't smoke detectors be replaced every 10 years anyway? Also, new code requires hard-wired, so even though you are probably grandfathered in, I would get a new hardwired one and install it as Pharkus said.

I'd recommend replacing them with new hardwired ones. If these had an extra wire (most do) to tie them together, you'll probably need to replace them all (good idea anyhow).

I disagree with Matthew however. Smoke alarms go off way before there is enough heat to cause the power to short. It's amazing how long power stays on in a fire anyhow. I've been inside with a hose line and found the overhead lights still on in a number of fires.

To me the insistence that all hard wired smoke alams have backup batteries is a little too much. The odds of having a fire while the power is out is minuscule, and I believe the odds of serious injury from ladder falls while changing batteries is worse. At least new there are units with 10 year built in backup batteries.

I bought the BRK 9120 and 7010 alarms which don't have batteries in 2015. Both are discontinued.