smoke detectors going off for no reason?

cibula11

on a related note, with regards to a co2 detector, how would you know if it was a false alarm or not?

Not to be nit picky, but CO2 is Carbon Dioxide. It's what you breath out. If you had one of those you'd be having frequent alarms (like on every exhale)
CO3 is carbon monoxide.

By the way, we installed some cheapo smoke alarms and they are the most sensitive things I have every seen, or heard. We open the oven, beeeep, we take a pot off the burner, beeeep. I guess it's better to be sensitive than not,but it is annoying.

Silk

Not to be nit picky, but Mono means "one". Carbon Monoxide is CO. I don't have any clue what CO3 is.

fireguy

CO3 is a brother to 3CPO.

Sorry, could not resist.

micromind

Several years ago, a friend had a similar problem. Over the course of several weeks, we narrowed it down to the smoke would occasionally alarm when a ceiling fan (on the same circuit) was turned on. It had an variable speed control switch.

I realize this is a bit extreme, but I took my oscilloscope over to their house, and connected it to the secondary of the power supply inside of the smoke. (This guy is an airplane mechanic, I think he enjoyed this more than I did!). In looking at the waveform, as near as I could tell, the fan speed control was causing a sort of reactive/capacitive distortion that happened to be magnified by the construction of the smokes power supply board. (that's techno-babble for 'it was messing it up' lol). We replaced the infinite speed control with a 3-position one; problem solved.

I realize your 3AM problem is not a fan speed control, but a couple of other things come to mind. Are you anywhere near an industrial area? A water pumping station? The reason I ask is these places usually have big motors and electronic soft-starts, VFDs etc. These items can send some pretty nasty harmonics back up the power line. How is your electric meter read? If it's read electronically, the reading signals could have an effect. That would also explain why it occurs at 3AM.

Probably the easiest solution is to simply replace it with a different brand. If you suspect a problem with the incoming power, you could ask the power co. to do a power quality analysis on your service. Around here, they usually will, free of charge.

I know all this sounds pretty far-fetched, but I sure wouldn't have guessed that a ceiling fan control could have set off a smoke.

Rob