An apparatus for controlling the temperature of a food liquid, comprising: - a tank for storing a food liquid, - a heat exchanger arranged in said tank, - a heat pump equipment connected with said heat exchanger and configured to supply a heated or refrigerated fluid, wherein: said tank comprises: - a base wall, - a side wall extending from said base wall along a longitudinal direction (X-X), - a lower opening formed in a lower portion of said side wall, - an upper opening, - a lower door for closing and opening said lower opening, said heat exchanger comprises: - an inlet duct configured to receive the fluid supplied by said heat pump equipment, - a coil portion connected to said inlet duct and configured to allow heat exchange between said fluid and the food liquid stored in the tank, - an outlet duct connected to said coil portion and configured to deliver the fluid coming from the coil portion to the heat pump equipment, characterized in that - said lower door is removably attached to said tank through attachment means that are configured to allow full disengagement of said lower door from said tank for opening said lower opening, - said inlet duct and said outlet duct pass through said lower door and are firmly attached to said lower door, - said coil portion is configured to pass through said lower opening to allow said heat exchanger to be put in said tank and pulled out from said tank upon disengaging said lower door from said tank and moving said lower door and the heat exchanger along a transverse direction (Y-Y), transversal to said longitudinal direction (X-X). - a tank for storing a food liquid, - a heat exchanger arranged in said tank, - a heat pump equipment connected with said heat exchanger and configured to supply a heated or refrigerated fluid, said tank comprises: - a base wall, - a side wall extending from said base wall along a longitudinal direction (X-X), - a lower opening formed in a lower portion of said side wall, - an upper opening, - a lower door for closing and opening said lower opening, - a base wall, - a side wall extending from said base wall along a longitudinal direction (X-X), - a lower opening formed in a lower portion of said side wall, - an upper opening, - a lower door for closing and opening said lower opening, said heat exchanger comprises: - an inlet duct configured to receive the fluid supplied by said heat pump equipment, - a coil portion connected to said inlet duct and configured to allow heat exchange between said fluid and the food liquid stored in the tank, - an outlet duct connected to said coil portion and configured to deliver the fluid coming from the coil portion to the heat pump equipment, - an inlet duct configured to receive the fluid supplied by said heat pump equipment, - a coil portion connected to said inlet duct and configured to allow heat exchange between said fluid and the food liquid stored in the tank, - an outlet duct connected to said coil portion and configured to deliver the fluid coming from the coil portion to the heat pump equipment, - said lower door is removably attached to said tank through attachment means that are configured to allow full disengagement of said lower door from said tank for opening said lower opening, - said inlet duct and said outlet duct pass through said lower door and are firmly attached to said lower door, - said coil portion is configured to pass through said lower opening to allow said heat exchanger to be put in said tank and pulled out from said tank upon disengaging said lower door from said tank and moving said lower door and the heat exchanger along a transverse direction (Y-Y), transversal to said longitudinal direction (X-X).