I just heard this 2 weeks ago but Firex recalled a lot of their CO and combo Smoke/CO detectors for false readings.
Like I said I just heard it from the supply house so if anyone recently bought one, check it out with the manufacturer.
As an electrician (as a lot of you already know I am
) when we wire new systems at 120 volts with battery back up, only BRK has a UL listed combination unit that will pass inspection. You can use any hard wired or plug in detector that is CO only but if you want that less cluttered look on your ceiling, go with BRK. They sound a CO warning verbally (sorry, but in English only) telling you where the cause is (user programmable location) at all CO detector locations and at what level it is in PPM.
OK so thats cool and I have these and trust them but I also have the digital display ones also. They tell you as you are sitting by the stove, not just when in alarm state, what the number is at a glance. You get to nip a problem before a detector goes off and you all feel nauseous. You could go through a long flu season and realize later it was CO levels that just weren't setting the detectors off! How much brain damage did that cause your children over months of not knowing? The digital ones are the extra protection I believe everyone should have! If you know me, you know I take my job seriously. I try to go above the norm.
OK, off my soap box.
Have a safe heating season! Scott