System and methods for controlling operating state of a heat transfer system are disclosed herein. The heat transfer system can include temperature sensor positioned at the fluid inlet line and the fluid outlet line and a heat exchanger between the fluid inlet line and the fluid outlet line. The heat transfer system can include a processor communicatively coupled to the first temperature sensor and the second temperature sensor. The processor can determine an inlet temperature of water flowing in the fluid inlet line and outlet temperature of water flowing in the fluid outlet line and can determine a delta temperature based on difference between the inlet temperature and the outlet temperature. Based on the inlet temperature and the delta temperature, the processor can determine an operating state of the heat transfer system.

A water heater system includes a controller configured to integrate control of both recovery and recirculation operations of a recovery pump and a recirculation pump. As such, a separate device, installation location, and power source (e.g., available outlet) is not needed with the controller. Because a single controller is configured to control both recovery and recirculation operations, additional control functions are available. The controller may be in communication with an internal controller of the water heater and configured to receive an error notification upon abnormal operation of the water heater. The controller can stop recovery and recirculation operations in response to an error notification, unlike with traditional water heating systems which may otherwise continue to function. The recovery and recirculation operations are based on a setpoint temperature of the water heater such that changes made to the setpoint temperature will automatically adjust in the recovery and recirculation operations.

The water heater may be configured to execute a normal operation in which a heating means is continuously operated in an ON state in a case where a required heat quantity is greater than or equal to a minimum heat quantity. The water heater may be configured to execute an intermittent operation in which the heating means is alternately and repeatedly operated in the ON state and an OFF state repeatedly in a case where the required heat quantity is less than the minimum heat quantity. The water heater may be configured to change a distribution ratio of a flow control mechanism in the normal operation and in the intermittent operation. An operating speed of the flow control mechanism in the intermittent operation may be faster than an operating speed of the flow control mechanism in the normal operation.

A heating system for a pool or spa includes at least one heating device and a controller. The controller may control and/or operate the at least one heating device in a pre-heat mode or a usage mode. The pre-heat mode may heat water of the pool or spa to a pre-heat temperature based on a first input received by the controller. The usage mode may heat the water to a set temperature greater than the pre-heat temperature based on a second input received by the controller after the first input.

A heating system for a pool or spa includes at least one heating device and a controller. The controller may control and/or operate the at least one heating device in a pre-heat mode or a usage mode. The pre-heat mode may heat water of the pool or spa to a pre-heat temperature based on a first input received by the controller. The usage mode may heat the water to a set temperature greater than the pre-heat temperature based on a second input received by the controller after the first input.

A water heater including an inflow terminal for connecting a tankless water heater to a cold water supply and an outflow terminal for connecting the tankless water heater to a tap. A fluid channel proves a fluid connection from the inflow terminal to the outflow terminal. A heat element arrangement is arranged at or within at least a section of the fluid channel for transferring heat to fluid present within the fluid channel. An electronic controller is configured to control a heating power provided to the heat element arrangement. A flow sensor is arranged at or within the fluid channel downstream the heat element arrangement. The electronic controller is further configured to detect the presence of air bubbles within the fluid channel based on a change of a flow signal provided by the flow sensor and to adapt the heating power provided to the heat element arrangement in reaction to the determination of air bubbles.

A water heater appliance may include a casing, a tank, a temperature sensor, a heating system, and a controller. The temperature sensor may be attached to the casing in thermal communication with the tank to detect a temperature thereof. The controller may be in operative communication with the heating system. The controller may be configured to initiate a heating cycle that includes receiving a setpoint request comprising a requested temperature value, detecting a first tank temperature value at the temperature sensor, generating a first modified temperature value less than the first tank temperature value, determining the requested temperature value is less than the first modified temperature value, setting a target setpoint to the first modified temperature value in response to determining the requested temperature value is less than the first modified temperature value, and directing the heating system according to the target setpoint.

A water heater appliance may include a casing, a tank, a temperature sensor, a heating system, and a controller. The temperature sensor may be attached to the casing in thermal communication with the tank to detect a temperature thereof. The controller may be in operative communication with the heating system. The controller may be configured to initiate a heating cycle that includes receiving a setpoint request comprising a requested temperature value, detecting a first tank temperature value at the temperature sensor, generating a first modified temperature value less than the first tank temperature value, determining the requested temperature value is less than the first modified temperature value, setting a target setpoint to the first modified temperature value in response to determining the requested temperature value is less than the first modified temperature value, and directing the heating system according to the target setpoint.

A processor for a controller of a water heater is configured to receive water heater control parameters and an output from a sensor indicating a measured temperature of water in the water heater. The processor is also configured to determine whether to enter an anti-stacking control mode or to enter a demand anticipation control mode. In the anti-stacking control mode the processor is configured to initiate a call for heat when the measured temperature reaches a trigger temperature, calculate a burner on delay value and set a second timer with the calculated value, and calculate a reduced activation time. In the demand anticipation control mode the processor is configured to increase the variable offset based on a frequency of the demand anticipation control mode being activated, initiate a call for heat, and control, based on the reduced activation time or the increased offset value, the burner.

A water heater system includes a controller configured to integrate control of both recovery and recirculation operations of a recovery pump and a recirculation pump. As such, a separate device, installation location, and power source (e.g., available outlet) is not needed with the controller. Because a single controller is configured to control both recovery and recirculation operations, additional control functions are available. The controller may be in communication with an internal controller of the water heater and configured to receive an error notification upon abnormal operation of the water heater. The controller can stop recovery and recirculation operations in response to an error notification, unlike with traditional water heating systems which may otherwise continue to function. The recovery and recirculation operations are based on a setpoint temperature of the water heater such that changes made to the setpoint temperature will automatically adjust in the recovery and recirculation operations.