100 gallon water heater not working. Ace Pelizon Plumbing found 100 gallon heater in back of property not working with error code 63. Spoke to technical support and found it was a negative air flow issue. Ran 2 inch pvc out of laundry and drained unit. Thoroughly cleaned tank out and turned water back on. Turned unit on and was given another code of 62. Removed burner tube from tank and thoroughly cleaned. Put back together and unit fired right up. Thermostat is set to 120. In front laundry drained tank and thoroughly cleaned out. Filled tank up and set thermostat to 120. No warranty. All work was approved.