Apparatus for controlling weeds, comprising a frame movable over a surface, at least a storage tank for hot liquid and a supply system for supplying hot liquid from said at least one storage tank to supply nozzles for dispensing the hot liquid, wherein a control system is provided for controlling the supply nozzles, wherein at least one nozzle supply is provided between the at least one storage tank and a series of supply nozzles, for feeding hot liquid to nozzles of said series of nozzles, which at least one nozzle supply is at least partly surrounded by an isolation tank filled with hot liquid.