How to troubleshoot a gas water heater
A typical gas water heater consists of a steel tank, a layer of insulation, and a sheet metal jacket. The bottom of the tank is heated by a fixed gas burner that is controlled by a thermocouple and a regulator valve. To vent excess heat and noxious fumes, a gas heater tank is equipped with a hollow tube, through its center, that connects to a house flue.