A water heater can include a baffle and a slab heat exchanger with at least two rows of heat exchanger tubes, each row comprising a plurality of heat exchanger tubes. At least one of the heat exchanger tubes comprises a tube and a plurality of fins on the exterior of the tube circumscribing the tube, wherein the outer edge of each fin of the plurality of fins is bent at least at the same three areas of each fin such that the bends form at least three flat or concave areas running along the length of the heat exchanger tube.

A water heater can include a heat source and a heat exchanger that transfers heat to the water. A header attached to the heat exchanger provides an inlet and an outlet for water to flow into and out of the heat exchanger. The header can also include an anode assembly that releasably attaches to the header. The anode assembly can be located at a bottom of the header so that an anode in the anode assembly remains in contact with the water when water is flowing through the heat exchanger.

A swimming pool heating system, including a heat pump and control of the compressor of the heat pump according to a number of non-zero power levels, is detailed. The system includes, for example, three power levels, the first level being close to 40% of the maximum compressor speed, the second level being close to 70% of the maximum compressor speed, and the third level being close to 100% of the maximum compressor speed.

Exemplary embodiments are disclosed of self-configuring ignition controls or control modules (e.g., 120V/240V automatic self-configuring combined ignition and pool control for gas fired pool heating equipment, etc.).

Exemplary embodiments are disclosed of self-configuring ignition controls or control modules (e.g., 120V/240V automatic self-configuring combined ignition and pool control for gas fired pool heating equipment, etc.).

An immersible bath unit is configured to be submerged in a bathtub while a user takes a bath in the bathtub, and to provide a source of heat to reduce the rate at which the bath water would otherwise cool naturally. The immersible bath unit is battery powered to eliminate the risk of electric shock associated with water heaters powered by commercial AC electric service.

The disclosed technology can include a bypass valve assembly having a partition that can fluidly separate an inlet and an outlet of a fluid heating system. A first bypass valve and a second bypass valve can be mounted to the partition and configured to permit a fluid to flow between the inlet and the outlet. The first bypass valve and the second bypass valve can be configured to transition between a closed state and an open state. The first bypass valve and the second bypass valves can each have a spring configured to transition the respective first and second bypass valve from the closed state in response to experiencing a pressure that is greater than or equal to a respective first or second predetermined pressure. The second predetermined pressure can be greater than the first predetermined pressure.

A portable bath tub water heater is provided that includes a water pump and a heating element to heat water in a bath tub, wherein the portable bath tub water heater is configured to recirculate bath tub water using inlet and outlet tubes at least partially submerged in the water. The portable bath tub water heater is configured to be disposed on and/or nearby the bath tub in any number of different ways. After usage, the portable bath tub water heater may be purged of any remaining water and stored for future use.

A portable bath tub water heater is provided that includes a water pump and a heating element to heat water in a bath tub, wherein the portable bath tub water heater is configured to recirculate bath tub water using inlet and outlet tubes at least partially submerged in the water. The portable bath tub water heater is configured to be disposed on and/or nearby the bath tub in any number of different ways. After usage, the portable bath tub water heater may be purged of any remaining water and stored for future use.

The disclosed technology includes systems and methods for operating a pool water heating system. The pool water heating system can include a heat pump, a supplemental heat source, a water temperature sensor, and a controller. The controller can be configured to receive water temperature data and, in response to determining that the temperature of the water is less than a threshold temperature, output a control signal to activate the heat pump. The controller can further determine an expected heating time that can be indicative of an amount of time required for the temperature of the water to be greater than or equal to the threshold temperature. The controller can also generate a heating schedule based at least in part on the expected heat time and a predetermined time of use. The heating schedule can be indicative of a heat pump operation time and a supplemental heat source operation time.