Abstract: A water heater can include a housing and a heating system disposed within the housing, where the heating system is configured to heat a fluid. The water heater can also include a switch coupled to the heating system, where the switch operates between a first position during normal operations and a second position during an outage. The water heater can further include a primary power source coupled to the switch, where the primary power source is configured to provide primary power to the heating system through the switch during the normal operations. The water heater can also include an uninterruptible power supply (UPS) coupled to the switch, where the UPS is configured to provide reserve power to the heating system through the switch during the outage, and where the UPS is integrated with the housing.

Abstract: A tankless water heater including a water inlet, a water outlet, a conductivity sensor, a temperature sensor, and a heating chamber connected to the water inlet and the water outlet wherein the heating chamber is configured to heat a flow of water received from the water inlet and output the flow of water to the water outlet. The water heating system can further include a controller communicably coupled to the conductivity sensor and the temperature sensor, where the controller calculates an adjusted conductivity of a flow of water through the water heater.

Abstract: A direct spark igniter for a fuel-fired heating appliance is provided with enhanced ignition performance in environments having substantial levels of both moisture and pollution. Such enhanced ignition performance is representatively achieved by the combination of (1) forming external annular ribs on the ceramic body portion of the igniter; (2) extending a top end of the igniter electrode rod into the body portion; (3) bending the igniter electrode and ground rods and angling them toward one another; and (4) knurling external side surfaces on lower end portions of the igniter electrode and ground rods.

Abstract: A direct spark igniter for a fuel-fired heating appliance is provided with enhanced ignition performance in environments having substantial levels of both moisture and pollution. Such enhanced ignition performance is representatively achieved by the combination of (1) forming external annular ribs on the ceramic body portion of the igniter; (2) extending a top end of the igniter electrode rod into the body portion; (3) bending the igniter electrode and ground rods and angling them toward one another; and (4) knurling external side surfaces on lower end portions of the igniter electrode and ground rods.

Abstract: A fuel-fired low NOx water heater extending along a vertical axis has a radiant fuel burner disposed in its combustion chamber. The entire burner combustion air quantity is delivered to the burner from outside the combustion chamber via a horizontally serpentined flow path extending through an internal portion of the water heater. This serpentined air inflow path configuration causes a substantial portion of particulate matter in the incoming combustion air to be removed therefrom before entering and potentially clogging the burner.