While visiting my mother-in-law, we wanted to get the smoke detector situation in her house up to par (this is in Massachusetts, we're from Europe, though). She has a natural gas fired forced air furnace in her basement; it blows warm air directly into various rooms instead of using radiators.
Above the furnace, we found the following fixture:
(Sorry for the overexposure, the lighting situation is not quite optimal there.)
To me, it looks a bit like the eviscerated remains of a smoke detector. What throws me off, though, is that it has two wire conduits leading to it: the bx conduit leads to a small box attached to the furnace, the smooth conduit leads directly to the breaker box. I'm used to smoke detectors running on an independent 9V battery, with no conduits. I'm also sure it's not just a broken light fixture, given the text on it says it's an "alarm". (The text also refers to detailed instructions on the inside of the base of the alarm, but the base is nowhere to be found.)
What is is thing and what would need to be done to repair it?
Best Answer
That looks like it was part of a whole house smoke detector system.
Smoke detectors do have a limited life and when they start failing folks just pull them out.
Since the detector was close to the furnace it could have been smoke , carbon monoxide or both. I would see if the other detectors in the home work and in any case get replacements that are compatible with the others. You may find that multiple units may not be functioning.
On several jobs I have had to replace every smoke detector only the thermal detectors were still functional. In some cases I could get the same or similar model in other cases I had to replace the bases as the new models did not fit but used the same wiring.
You may be able to get more info off of the ring that is still there but getting a complete head will help you find compatible units.