Our Kidde Carbon Monoxide keeps going off?

well, without knowing the model number to look up the manual, when is gives you a number like that, it is telling you the CO reading in the air, without raising any alarms yet, i would open a few windows in the area, take everyone in the house for a drive to home depot, spend the additional $40 and buy a new one, take it home set it up, close the windows again and wait, if this one goes off with the near same code, get everyone out, CO is scary stuff, if enough is in the air it will put you down fast and you wont wake up. at 217 parts per million is considered medium exposure, dizziness, flu like symptoms, when it gets close to 400ppm brain damage and death, ideally CO levels should be under 30ppm, anything above 50ppm and we will start reacting