A breathing apparatus (1) is disclosed comprising an inspiratory channel (3), an expiratory channel (4), a patient interface (5), an oxygen valve (13) and a blower (7) comprising blower driving means (9). The blower (7) is arranged to produce a flow of air to the inspiratory channel (3). The oxygen valve (13) is configured to selectively deliver a flow of oxygen to the inspiratory channel (3). The breathing apparatus further comprises a control unit (19) configured to control the blower driving means (9) so that the blower (7) produces substantially no flow of air to the inspiratory channel (3) during a time period (tp). The present disclosure further relates to a method (100) of controlling operation of a breathing apparatus (1), a computer program and a computer program product (300) for performing a method (100) of controlling operation of a breathing apparatus (1).
