Abstract: A control system for a fan coil of an air-conditioner having a fan for heat exchange, and a coil unit through which cool or hot water circulates to cool or heat the room by heat exchange with the room air, wherein an automatic change is carried out between a cooling operation and a heating operation, referring to the temperature of distributed cool or hot water detected by a water temperature sensor, and a room temperature is controlled by opening or closing an electromagnetic valve disposed in a water distribution system, referring to a room temperature detected by a room temperature sensor. When the system is turned on from its inoperative state, the electromagnetic valve is forcibly opened for a predetermined period of time for the control system for a fan coil to sufficiently detect the temperature of cool or hot water, and to prevent an erroneous change of operation.