What’s wrong with this picture? Not sure where to start. Sometimes I see negative or flat slopes on gas appliance flues. The slope on this water heater flue is one of the worst I have seen. It is not going to draft properly and is likely spilling CO back into the house. It is situated next to a 40 year old furnace that could have a cracked heat exchanger or other issues that could also produce CO. What’s worse is that this house had no CO detectors. It’s amazing to me how many houses don’t have working smoke or CO detectors. All too often you hear about a tragedy where people die from CO poisoning or in fires because of missing or non working detectors. Be sure you have an adequate number of detectors and that they are working properly. Be safe out there. Thanks for stopping by. See you in 2 weeks for another installment of Postcards from the Field!