Abstract
An experimental investigation was made on the widely used (in Iraq), domestic water heater (Fire King Co. Product). It consists of a combustion chamber, fire tube, chimney, water jacket, fuel tank, insulating material and fuel controller. The heater uses Kerosene as fuel. An attempt was made to improve the combustion efficiency by modifying the combustion process in the burner. And also, increasing the heat transfer between the burned gases in the fire tube and the water by modifying the fire tube. Tests were made on non flow system with thermostat setting on the (hot) position of the controller. Comparisons were made according to fuel consumption, efficiency and time to reach steady state. The result in general, indicates significant improvement of efficiency and saving in fuel, besides reducing the time required to reach the steady state.