Pros: New A.O. Smith water heaters have stainless steel spark arrestors.
Cons: Any water heaters produced between 2003 and 2008 with Cordite flame arrestors.
All A.O Smith water heaters produced from around 2003 to 2008 with the Cordite flame arrestor have the potential to have problems with the pilots and burners going out due to lack of oxygen because the cordite flame arrestor clogs easily preventing the pilot/burner area from getting enough oxygen. All you have to do is bypass the arrestor by unsealing the burner area to allow some air to get to the pilot and burner. You can do this by cutting away some or all of the rubber gasket (" the main burner tube seal") where it goes through the "inner" door. Or you could just drill a small hole through the inner door. In either case, after creating an air passage, make sure the insulation on the inside of the inner door doesn't obstruct the passage. Doing this will take care of the lack of oxygen problem and your water heater will work better like the ones produced previous to 2003. I'm hoping the new heaters they are making today with the stainless steel spark arrestors will work better. A.O. Smith was a good water heater for most of its history.