Owner contacted me via email about a water heater flue back drafting. I went by the home and found a water hester installed in a utility room with a washer, dryer and a high efficiency furnace. There is currrently no combustion air into this utility room, there was at one time but they have since been blocked so when the furncae kicks on it is backdrafting the water heater flue. When the door to the room is open the issue does not occur. The home owner is going to install a louverd door into the room or cut combustion air openings into the existing door to cure the issue. Once done he will contact me so I can verify it has been completed. Until completed he is going to make sure the door to the utility room is left open.