Ok… Carbon monoxide is not a joke. If it’s detecting 999 PPM and it’s asked you to read a manual, get out now. Also, the carbon monoxide alarm will have to be replaced because it cannot handle that much CO. The basement is where the furnace is, So DO NOT GO NEAR THE FURNACE. You will instantly pass out. If you ever get new carbon monoxide detectors, and it’s still detects 999 PPM replace your entire furnace. If this was helpful, you’re welcome.
