We have a natural gas company that uses high CO counts coming from the exhaust of a 90% furnace to indecate the furnace has heat ex. problems or possible cracks.
What are normal CO counts for a NG furnace running correctly. If the furnace had a heat ex. crack the fact that more fresh air would be brought into the gases of combutions and so the CO counts would be less. Am I thinking this wrong. See what you guys think. Thanks for the help.