A respiratory assistance apparatus adapted to deliver a gases flow to a user or patient, the apparatus comprising: a housing provided with a heater (6, 25); a chamber comprising at least one chamber port configured to be connected to at least one intermediate passageway, the housing being configured to receive the chamber; and a controller (71, 73), the controller (71, 73) being operative to control the apparatus to operate according to a respiratory mode and a disinfection mode, and wherein the apparatus is arranged such that in the respiratory mode, a humidifier of the apparatus humidifies the gases flow prior to delivery of the gases flow to the user or patient, wherein the humidifier comprises the chamber, wherein the humidifying comprises the controller controlling the heater to heat water in the chamber such that the gases flow passes over the water and is humidified by vapour generated from the heated water; wherein during a duration of the disinfection mode the controller is operative to control the heater (6, 25) to heat water in the chamber to produce vapour at or above a target dewpoint temperature; wherein the apparatus is arranged such that, in use during the duration of the disinfection mode when the at least one intermediate passageway is connected to the chamber port: the vapour produced by heating the water in the chamber is delivered through the at least one chamber port to the at least one intermediate passageway connected to the chamber by the chamber port, to disinfect the at least one intermediate passageway with moist heat, wherein the vapour is at or above the target dewpoint temperature; wherein the apparatus is configured by the controller subsequent to the disinfection mode to be operative in a drying mode, in which drying mode the at least one intermediate passageway is dried. a housing provided with a heater (6, 25); a chamber comprising at least one chamber port configured to be connected to at least one intermediate passageway, the housing being configured to receive the chamber; and a controller (71, 73), the controller (71, 73) being operative to control the apparatus to operate according to a respiratory mode and a disinfection mode, and wherein the apparatus is arranged such that in the respiratory mode, a humidifier of the apparatus humidifies the gases flow prior to delivery of the gases flow to the user or patient, wherein the humidifier comprises the chamber, wherein the humidifying comprises the controller controlling the heater to heat water in the chamber such that the gases flow passes over the water and is humidified by vapour generated from the heated water; wherein during a duration of the disinfection mode the controller is operative to control the heater (6, 25) to heat water in the chamber to produce vapour at or above a target dewpoint temperature; wherein the apparatus is arranged such that, in use during the duration of the disinfection mode when the at least one intermediate passageway is connected to the chamber port: the vapour produced by heating the water in the chamber is delivered through the at least one chamber port to the at least one intermediate passageway connected to the chamber by the chamber port, to disinfect the at least one intermediate passageway with moist heat, wherein the vapour is at or above the target dewpoint temperature; wherein the apparatus is configured by the controller subsequent to the disinfection mode to be operative in a drying mode, in which drying mode the at least one intermediate passageway is dried.