An air-conditioning system comprising: a heat source side unit configured to heat or cool refrigerant; a use side unit configured to heat or cool water; a relay unit configured to cause heat exchange to be performed between the refrigerant and the water; a refrigerant circuit in which the heat source side unit and the relay unit are connected by a refrigerant pipe to allow the refrigerant to circulate; a water circuit in which the use side unit and the relay unit are connected by a water pipe to allow the water to circulate; a controller configured to operate in a trial operation mode in which a trial operation is performed when the refrigerant circuit or the water circuit is installed, and configured to operate in a normal operation mode in which a normal operation is performed; a first setting unit configured to switch the trial operation mode and the normal operation; a second setting unit configured to switch a target for the trial operation in the trial operation mode between the refrigerant circuit and the water circuit; and a third setting unit configured to switch activation and non-activation of invalidation of an error indicating an abnormal state, wherein the controller is configured to invalidate an error that occurs in the water circuit when the trial operation mode is set by the first setting unit, a target for the trial operation in the trial operation mode is set to the refrigerant circuit by the second setting unit, and invalidation of an error is set to be active by the third setting unit, and invalidate an error that occurs in the refrigerant circuit when the trial operation mode is set by the first setting unit, a target for the trial operation in the trial operation mode is set to the water circuit by the second setting unit, and invalidation of an error is set to be active by the third setting unit. a heat source side unit configured to heat or cool refrigerant; a use side unit configured to heat or cool water; a relay unit configured to cause heat exchange to be performed between the refrigerant and the water; a refrigerant circuit in which the heat source side unit and the relay unit are connected by a refrigerant pipe to allow the refrigerant to circulate; a water circuit in which the use side unit and the relay unit are connected by a water pipe to allow the water to circulate; a controller configured to operate in a trial operation mode in which a trial operation is performed when the refrigerant circuit or the water circuit is installed, and configured to operate in a normal operation mode in which a normal operation is performed; a first setting unit configured to switch the trial operation mode and the normal operation; a second setting unit configured to switch a target for the trial operation in the trial operation mode between the refrigerant circuit and the water circuit; and a third setting unit configured to switch activation and non-activation of invalidation of an error indicating an abnormal state, wherein the controller is configured to invalidate an error that occurs in the water circuit when the trial operation mode is set by the first setting unit, a target for the trial operation in the trial operation mode is set to the refrigerant circuit by the second setting unit, and invalidation of an error is set to be active by the third setting unit, and invalidate an error that occurs in the refrigerant circuit when the trial operation mode is set by the first setting unit, a target for the trial operation in the trial operation mode is set to the water circuit by the second setting unit, and invalidation of an error is set to be active by the third setting unit.