Hi Sue; Yes, the dealer found spaces in the seals between the furnace & the outside, so it was sucking in outside air.. Finally got the hot water heater fixed after 3 weeks of waiting and 2 days of them working on it. I also got a CO detector with a number read out on it for $29 from Target. It's a "Nighthawk" brand. The ones without a # display trigger at 100ppm, but the EPA set the limit for 8 hour exposure at 50ppm! So the most popular sellers can let you get sick & not warn you that something is not right! Take care, Gary Violence is not strength, Compassion is not weakness. From Camelot. [Posted in FML issue 1496]