An air-conditioning and warm water supply unit, comprising: a heat exchanger configured to transfer heat from a refrigerant to a fluid; a fluid inflow tube connected to the heat exchanger, and configured to pass the fluid flowing into the heat exchanger; a fluid outflow tube connected to the heat exchanger, and configured to pass the fluid flowing from the heat exchanger; a fluid supply part connected to a forward external pipe, the forward external pipe being configured to pass the fluid flowing to an air conditioner disposed in an air-conditioned space; a first supply tube connecting the fluid outflow tube and the fluid supply part; a fluid return part connected to a return external pipe, the return external pipe configured to pass the fluid returning from the air conditioner; a first return tube connecting the fluid inflow tube and the fluid return part; a warm water supply tank configured to heat water by heat supplied from the fluid; a second supply tube connecting the fluid outflow tube and the warm water supply tank; a second return tube connecting the fluid inflow tube and the warm water supply tank; a switching mechanism configured to switch between a first state in which the fluid flows from the fluid outflow tube to the air conditioner via the first supply tube, and a second state in which the fluid flows from the fluid outflow tube to the warm water supply tank via the second supply tube; a pump arranged to the fluid outflow tube or the fluid inflow tube; a flow rate detection means configured to detect a flow rate of the fluid; and a control unit, characterized in that the flow rate detection means is arranged to the fluid outflow tube or the fluid inflow tube, the control unit is configured to determine that the flow rate is abnormal when the fluid flow rate detected by the flow rate detection means is in a predetermined range, and when the flow rate is determined to be abnormal, the control unit is configured to confirm whether the switching mechanism is in the first state or the second state, assess whether the abnormal flow rate occurs while the fluid flowing to the air conditioner or the abnormal flow rate occurs while the fluid flowing to the warm water supply tank, and output an assessment result. a heat exchanger configured to transfer heat from a refrigerant to a fluid; a fluid inflow tube connected to the heat exchanger, and configured to pass the fluid flowing into the heat exchanger; a fluid outflow tube connected to the heat exchanger, and configured to pass the fluid flowing from the heat exchanger; a fluid supply part connected to a forward external pipe, the forward external pipe being configured to pass the fluid flowing to an air conditioner disposed in an air-conditioned space; a first supply tube connecting the fluid outflow tube and the fluid supply part; a fluid return part connected to a return external pipe, the return external pipe configured to pass the fluid returning from the air conditioner; a first return tube connecting the fluid inflow tube and the fluid return part; a warm water supply tank configured to heat water by heat supplied from the fluid; a second supply tube connecting the fluid outflow tube and the warm water supply tank; a second return tube connecting the fluid inflow tube and the warm water supply tank; a switching mechanism configured to switch between a first state in which the fluid flows from the fluid outflow tube to the air conditioner via the first supply tube, and a second state in which the fluid flows from the fluid outflow tube to the warm water supply tank via the second supply tube; a pump arranged to the fluid outflow tube or the fluid inflow tube; a flow rate detection means configured to detect a flow rate of the fluid; and a control unit, characterized in that the flow rate detection means is arranged to the fluid outflow tube or the fluid inflow tube, the control unit is configured to determine that the flow rate is abnormal when the fluid flow rate detected by the flow rate detection means is in a predetermined range, and when the flow rate is determined to be abnormal, the control unit is configured to confirm whether the switching mechanism is in the first state or the second state, assess whether the abnormal flow rate occurs while the fluid flowing to the air conditioner or the abnormal flow rate occurs while the fluid flowing to the warm water supply tank, and output an assessment result.