A mobile negative pressure wound therapy (NPWT) device, comprising: an inlet to be in fluid flow connection with a wound site; a canister in fluid flow connection with the inlet for collection of liquid from the wound site; a pump in fluid flow connection with the canister for establishing a negative pressure in the canister; a pressure sensor arranged to sense a pressure in the canister; and control circuitry for controlling operation of the NPWT device, the control circuitry being configured to: receive a request for start-up of the NPWT device; initiate, in response to the request for start-up, a start-up test sequence for the NPWT device; acquire, from the pressure sensor, a first signal indicating the pressure in the canister; evaluate the first signal acquired from the pressure sensor; when the acquired first signal indicates a pressure less negative than a predefined threshold pressure: control the pump to operate during a predefined time period; acquire a second signal from the pressure sensor after the predefined time period; proceed with the start-up test sequence; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode; and when the acquired first signal indicates a pressure more negative than the predefined threshold pressure: proceed with the start-up test sequence without controlling the pump to operate during the predefined time period; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode. an inlet to be in fluid flow connection with a wound site; a canister in fluid flow connection with the inlet for collection of liquid from the wound site; a pump in fluid flow connection with the canister for establishing a negative pressure in the canister; a pressure sensor arranged to sense a pressure in the canister; and control circuitry for controlling operation of the NPWT device, the control circuitry being configured to: receive a request for start-up of the NPWT device; initiate, in response to the request for start-up, a start-up test sequence for the NPWT device; acquire, from the pressure sensor, a first signal indicating the pressure in the canister; evaluate the first signal acquired from the pressure sensor; when the acquired first signal indicates a pressure less negative than a predefined threshold pressure: control the pump to operate during a predefined time period; acquire a second signal from the pressure sensor after the predefined time period; proceed with the start-up test sequence; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode; and when the acquired first signal indicates a pressure more negative than the predefined threshold pressure: proceed with the start-up test sequence without controlling the pump to operate during the predefined time period; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode. receive a request for start-up of the NPWT device; initiate, in response to the request for start-up, a start-up test sequence for the NPWT device; acquire, from the pressure sensor, a first signal indicating the pressure in the canister; evaluate the first signal acquired from the pressure sensor; when the acquired first signal indicates a pressure less negative than a predefined threshold pressure: control the pump to operate during a predefined time period; acquire a second signal from the pressure sensor after the predefined time period; proceed with the start-up test sequence; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode; and control the pump to operate during a predefined time period; acquire a second signal from the pressure sensor after the predefined time period; proceed with the start-up test sequence; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode; and when the acquired first signal indicates a pressure more negative than the predefined threshold pressure: proceed with the start-up test sequence without controlling the pump to operate during the predefined time period; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode. proceed with the start-up test sequence without controlling the pump to operate during the predefined time period; and allow, unless the NPWT device failed at least one test in the start-up test sequence by failing to fulfill at least one criterion in a set of predefined criteria, the NPWT device to transition to therapy mode.