Gas-fired water heater having plate-mounted removable bottom end burner and pilot assembly

摘要

A fuel-fired water heater has a combustion chamber disposed beneath the storage tank portion of the water heater. The bottom side wall of the combustion chamber is defined by an annular perforated wall structure with a perforated mounting plate structure being removably secured to the underside of the wall structure over the central opening therein. A burner and associated pilot/thermocouple assembly are secured to the upper side of the mounting plate and project upwardly into the combustion chamber, with the piping and wiring of the burner and pilot/thermocouple assembly extending externally beneath the combustion chamber, outwardly through a side wall access passage, and then turning upwardly along the outside of the water heater for connection to a thermostatic fuel valve. To remove the bottom plate-mounted burner and pilot/thermocouple assembly the fuel supply piping must first be decoupled from the thermostatic valve, thereby assuring that the access plate cannot be removed while the burner is firing. The combustion chamber is essentially sealed to prevent combustion air inflow thereto except through the perforations in its bottom side wall structure. These perforations are configured and sized to permit upward combustion air inflow therethrough into the combustion chamber with a minimal pressure drop, while also acting as flame arrestors to hinder downward flame flow therethrough potentially caused by upward inflow of flammable vapors and subsequent ignition thereof within the interior of the combustion chamber.