Water heating device intended for a single or multi-station weeding device, comprising a boiler (k), a fuel pump (b), a nozzle (i) and a diffusion lance or ramp (m), the device being able to provide: a. low pressure water at a regulated and constant temperature of 95 to 99 ° Celsius at the nozzle outlet (i) placed on the diffusion lance or ramp (m), b. as well as by the formation of water droplets of a controlled size varying from 0.5 to 1.5 mm at the nozzle outlet (i), the device comprising: - A servo-control suitable for managing the temperature of the boiler according to the principle of a continuously controlled water flow at a constant temperature of 120 ° Celsius at the boiler outlet (k), composed of: ∘ an automaton (j) equipped with a controlling program of the weeding device to satisfy a particular process of permanent control of the weeding device, ∘ a flow switch (a) connected to the automaton (j) indicating the presence of water flow, ∘ a temperature sensor at the boiler outlet (f) connected to the controller permanently indicating the water temperature at the boiler outlet, ∘ a PWM variator (d) which immediately and at any time transcribes the commands from the programmed automaton (j) to the fuel pump (b) in order to vary the fuel flow according to the program, ∘ a PWM variator (h) which receives information from the programmed automaton (j) and controls the water flow to the water pump (g), - A fuel supply flow permanently managed by the servo-control, fuel flow varying according to the desired water flow to obtain a constant temperature of 120 ° Celsius at the boiler outlet, - A variable water flow managed by the servo-control ensuring hot water production at a constant temperature of 120 ° degree Celsius (plus or minus one degree) at the boiler outlet (k), equipped with a nozzle (i) whose the orifice is between a diameter of 4.5 and 5 mm, all to satisfy the formation of water droplets at the outlet of the nozzle (i) of a size varying between 0.5 and 1.5 mm, while the water temperature at this same place is constant varying between 95 and 99 ° Celsius. a. low pressure water at a regulated and constant temperature of 95 to 99 ° Celsius at the nozzle outlet (i) placed on the diffusion lance or ramp (m), b. as well as by the formation of water droplets of a controlled size varying from 0.5 to 1.5 mm at the nozzle outlet (i), - A servo-control suitable for managing the temperature of the boiler according to the principle of a continuously controlled water flow at a constant temperature of 120 ° Celsius at the boiler outlet (k), composed of: ∘ an automaton (j) equipped with a controlling program of the weeding device to satisfy a particular process of permanent control of the weeding device, ∘ a flow switch (a) connected to the automaton (j) indicating the presence of water flow, ∘ a temperature sensor at the boiler outlet (f) connected to the controller permanently indicating the water temperature at the boiler outlet, ∘ a PWM variator (d) which immediately and at any time transcribes the commands from the programmed automaton (j) to the fuel pump (b) in order to vary the fuel flow according to the program, ∘ a PWM variator (h) which receives information from the programmed automaton (j) and controls the water flow to the water pump (g), ∘ an automaton (j) equipped with a controlling program of the weeding device to satisfy a particular process of permanent control of the weeding device, ∘ a flow switch (a) connected to the automaton (j) indicating the presence of water flow, ∘ a temperature sensor at the boiler outlet (f) connected to the controller permanently indicating the water temperature at the boiler outlet, ∘ a PWM variator (d) which immediately and at any time transcribes the commands from the programmed automaton (j) to the fuel pump (b) in order to vary the fuel flow according to the program, ∘ a PWM variator (h) which receives information from the programmed automaton (j) and controls the water flow to the water pump (g), - A fuel supply flow permanently managed by the servo-control, fuel flow varying according to the desired water flow to obtain a constant temperature of 120 ° Celsius at the boiler outlet, - A variable water flow managed by the servo-control ensuring hot water production at a constant temperature of 120 ° degree Celsius (plus or minus one degree) at the boiler outlet (k), equipped with a nozzle (i) whose the orifice is between a diameter of 4.5 and 5 mm, all to satisfy the formation of water droplets at the outlet of the nozzle (i) of a size varying between 0.5 and 1.5 mm, while the water temperature at this same place is constant varying between 95 and 99 ° Celsius.