Water heater and gas burner

摘要

A water heater includes a tank 10 arranged inside a casing 20 with a burner 16 below the tank so that a heat exchange zone 15 surrounding the tank receives the combustion products. The tank 10 is supported on three edge contact projections 26 resting on ledges 27 located a substantial distance up the sides of the tank. The casing 20 narrows in the upwards direction and a heat shield 30 is coaxially located in the lower portion of the casing where the hottest gases are. A downwardly extending flue 49 outside the casing provides a heat trap. The burner 15 has a burner ring 60 with a unique arrangement of burner ports 62 and a secondary air guide 80. The thermostat probe 14 for the gas valve 17 passes through the heat exchange zone 15 to be intentionally affected by the heat and reduce the achieved operating temperature differential.