Question:
This morning I found that the smoke detector in my basement was sounding off for about 5-10 seconds every 20-30 minutes or so. This detector is powered from the house wiring, not from batteries. It is apparently an ionization type detector, since there is a radioactive materials warning on it. The manufacturer is Tellus Industries of Toronto; no such company is in the current Metro Toronto phone book.

It has previously sounded only when I was using power tools in the basement and making dust with a bit of smoke in it. There is no smell of smoke nor any unusual dust now. The air slots in the outer cover are not clogged with dust, and the cover does not appear to be designed to be opened for cleaning inside it -- it would need to be opened with a screwdriver and then would probably expose live contacts.

I stopped it for now by turning off the breaker, and if I don't hear any other advice I suppose I'll replace the detector. Any other advice?

Answer: - Our detectors are powered primarily from AC as well, but they do have 9V batteries as backup. When the battery goes low in ours, they "chirp" once, every 5-10 minutes. VERY annoying in the middle of the night! Replacing the battery cures the chirps.

-I also have one of these kind of detectors that is powered by the house current but has a GE NiCad (9V) battery backup. I also recently experienced the same problem that Mark Brader had with the intermittant sounding occurring, but it was not at the normal "test" level of noise. I took off the cover, suspecting dust or something else and blew it out. Still didn't fix it.

Then, I noticed that the yellow light on the front that shows that the recharging process is active was *NOT* on. So I took out the battery, did the "tongue test", realized that the battery was still good, and reconnected it. Now the recharge light lit up. No more intermittant noise, so I wrote it up to the dectector letting me know that something was not connected correctly, namely the recharging circuit. How the recharger got "off" is still a mystery. That was about 2 weeks ago. Up till now, no more intermittant dectector noises.