Abstract: A water heater includes power distribution circuitry receiving primary power and secondary power. The water heater includes a heat exchange system including at least one component powered via the primary power and configured to transfer heat between a refrigerant and water. The water heater includes at least one heater operably coupled with and configured to heat at least one portion of the heat exchange system. The water heater includes switching circuitry electrically interposing the power distribution circuitry and the at least one heater to selectively power the at least one heater via the primary power in a first condition of the switching circuitry and via the secondary power when the primary power is unavailable in a second condition of the switching circuitry.

Abstract: A recirculating bath includes a main power input configured to receive an alternating current and a heating element that is selectively coupled to the main power input. The heating element is selectively coupled to the main power input in response to an activation signal having a duty cycle. The duty cycle of the activation signal is determined based on a voltage of the alternating current, with the duty cycle being reduced in response to an increase in the voltage of the alternating current. The heating element is thereby de-rated at higher alternating current voltages. A power unit coupled to the main power input provides direct current having a voltage independent of the alternating current voltage to portions of the recirculating bath, such as direct current motors coupled to a compressor and recirculating pump. The recirculating bath is thereby configured to operate with a range of alternating current voltages.