Method and apparatus for controlling water heater, water heater, and controlling system thereof

A method for controlling a water heater, the method comprising:

• receiving report information transmitted by a device of a user at a predetermined frequency;
• determining whether the user is moving toward a location of the water heater according to the user location information comprised in the report information;
• determining that the user is moving toward the location of the water heater, and then determining whether a distance between a current user location and the location of the water heater is less than a second predetermined distance;
• determining that the distance between the current user location and the location of the water heater is less than the second predetermined distance, and then starting the water heater to heat when the water heater is in a non-heating state, and further determining whether the distance between the current user location and the location of the water heater is less than a first predetermined distance, wherein the second predetermined distance is greater than the first predetermined distance;
• and
• determining that the distance between the current user location and the location of the water heater is less than the first predetermined distance, and then determining that the user is coming back, and turning on a return water pump to permit water outputted from a water outlet of the water heater to return to the water heater through a water return port.