@robtillaart. Yep, I have, and that's what the trouble is. It should be that the co2 sensor handles up to around 50 deg C fine, but when I am using it near a heat source that's not even close to that range it begins to act strangely. For instance, the Co2 levels will suddenly drop to an abnormally low level, and it'll stay that way for a bit. Not sure if it's a problem with the sensor, or if the heat is affecting the environment around it