The present invention generally relates to fuel-fired water heaters and, in representatively illustrated embodiments thereof provides a specially designed high efficiency downfired gas water heater.
Fuel-fired storage type water heaters are commonly used in both commercial and residential applications to provide on-demand hot water to various types of hot water-utilizing plumbing fixtures such as sinks, showers, dishwashers and the like. In one conventional construction thereof, this type of water heater has a tank for holding pressurized water to be heated, a combustion chamber with a fuel burner therein for generating hot combustion products, and a flue extending through the tank interior. During firing of the water heater, hot combustion gases generated by the burner flow through the flue, with heat from the combustion gases being transferred from within the flue to stored tank water through which the flue extends.
With increasing demands for both higher energy efficiency and lowered water heater production costs, it has become necessary to design fuel-fired water heaters which are both simpler in structure and capable of transferring a greater percentage of burner-generated combustion heat to the stored tank water. It is to these design goals that the present invention is primarily directed.