Today I came to Rai’s Evanston home because uses the water heater is not working. Upon inspection I found the fan on top of the unit is very hot and not turning on but I can hear it humming. This most ;I key means the fan assembly has failed and needs to be replaced. I have offered a diagnostic to see if I can get it started but Rai has declined at this time and just wants a quote for a new fan. I have explained that the water heater is 11 years old, at it’s level expectancy, and out if warranty. Because of these reasons, I recommend replacement. The venting size for a 50 gallon direct vented tank is ideally 3” and not 2”.