The present invention becomes possible to employ a main microprocessor with a relatively lower number of input ports, whereby while maintaining the performance and function of a water heater, the cost of a control apparatus is cut down. Some of sensors, adapted for measurement of various parameters which are for use in operational control of the water heater and in need of immediate response, are connected to a main microprocessor 31. The other sensors that are not in need of an immediate response, such as an ambient temperature sensor 36, are connected only to a sub microprocessor 32 if the main microprocessor 31 does not have any extra analog signal input port. The sub microprocessor converts an analog signal from the sensor 36 which is connected only to the sub microprocessor into digital data. And the sub microprocessor transmits the digital data to the main microprocessor through communication therewith.

A heat exchanger according to the present disclosure includes a plurality of tubes through which heating water flows, a housing having an interior space in which the plurality of tubes are disposed and through which a combustion gas passes, the housing including a plurality of flow passage caps connected with distal ends of the plurality of tubes to cause the heating water to flow through the flow passage caps, a temperature sensor brought into close contact with an area between two flow passage caps adjacent to each other among the plurality of flow passage caps to obtain a temperature, and a bracket coupled to the housing to bring the temperature sensor into close contact with the area between the adjacent two flow passage caps.

The present disclosure relates to a method and a system for preventing freezing when a four-way valve in a heat pump water heater is failed, which includes following acts: In act S1, it is judged that whether current water temperature T is lower than a preset minimum temperature T.sub.min , for the water tank, if yes, perform act S2; if no, perform act S1 again. In act S2, it is judged that whether a cooling rate Td of the current water temperature T is greater than or equal to a preset rate ΔT; or, it is judged that whether the current water temperature T satisfies T<T.sub.min−a and whether T<T.sub.min−a stands for a first time period t1, in which a is a limit value of a temperature difference; if at least one yes, perform act S3, otherwise, return to act S1. In act S3, a heat pump system is controlled to stop and an electric auxiliary heating system is started. By judging whether a cooling rate Td of the current water temperature T is greater than or equal to a preset rate ΔT; or by judging whether the current water temperature T satisfies T<T.sub.min−a and whether T<T.sub.min−a stands for a first time period t1, it may be judged precisely that whether the four-way valve is failed, which avoids a misjudgment.

Disclosed herein are WIFI and could enabled temperature control systems. The temperature control systems are configured to receive user temperature settings and preferences, and control a water heater based on the user temperature settings and preferences. The temperature control systems include two or more sampling rates for enabling a higher efficiency of operation compared to conventional water heaters.

A water heater system includes a water heater having a first water outlet and a second water outlet. The water heater system further includes a flow detection device coupled to the first water outlet to detect a water flow through the first water outlet. The water heater system also includes a flow control valve fluidly coupled to the second water outlet. The flow control valve is configured to control a flow of water through the second water outlet based on whether the water flow through the first water outlet is detected by the flow detection device.

A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor configured to detect an outdoor temperature, a second temperature sensor provided in heating pipes connected to a heating device, and a controller. Based on a first sensing value of the first temperature sensor, the controller may be configured to control a compressor, control power to a boiler, and/or calculate an expected efficiency of the heat pump. Based on the expected efficiency and/or a second sensing value of a second temperature sensor, the controller may be configured to control power to the boiler.

A heat pump may include a compressor configured to compress a refrigerant, a first temperature sensor provided in heating pipes connected to a heating device that heats an indoor space to sense a temperature of fluid flowing through the heating pipes, and a controller. The controller may be configured to determine whether a boiler is operating to heat an indoor space or is operating to supply hot water based on a sensing value of the first temperature sensor. The compressor may operate when the controller determines that the boiler is not operating to heat the indoor space and/or determines that the boiler is operating to supply hot water.

Disclosed herein are WIFI and could enabled temperature control systems. The temperature control systems are configured to receive user temperature settings and preferences, and control a water heater based on the user temperature settings and preferences. The temperature control systems include two or more sampling rates for enabling a higher efficiency of operation compared to conventional water heaters.

A heat pump water heater can include a water tank and a refrigerant circuit that can be in fluid communication with an evaporator coil, a condenser coil, and a compressor. The heat pump water heater can include a fan configured to move air across the evaporator coil, a temperature sensor, and a controller. The controller can be configured to receive temperature data from the temperature sensor and, in response to the temperature data indicating a temperature less than a predetermined temperature threshold, output instructions for the compressor to deactivate and the fan to move air across the evaporator coil.

The present disclosure discloses a defrosting control method, a central controller and a heating system. The defrosting control method comprises: heating fluid in a flow passage between an inlet and an outlet of a first heat source by a second heat source, at least in a part of process of defrosting by the first heat source; acquiring an operation parameter of the first heat source, wherein the operation parameter comprises a water outlet temperature and/or a water return temperature and/or an operation parameter of a compressor of the first heat source, comparing a current value of the acquired operation parameter with a preset range of the operation parameter, and adjusting a heat exchange amount between the second heat source and the fluid when the acquired current value is within the preset range. The defrosting control method, the central controller and the heating system provided by the present disclosure can improve the defrosting efficiency while considering the heating comfort, and ensure the stable operation of the defrosting process.