In some embodiments, a negative pressure apparatus includes a negative pressure source configured to provide negative pressure via a fluid flow path to a wound dressing placed to create a seal over a wound, a pressure sensor, and a controller. The controller can be configured to operate the negative pressure source in a first mode and determine a change in pressure in the fluid flow path over a period of time based on a plurality of measurements by the pressure sensor. In response to a determination that pressure in the fluid flow path is decreasing, the controller can operate the negative pressure source in a second mode in which greater amount of negative pressure is provided than in the first mode. In response to a determination that pressure in the fluid flow path is not decreasing, the controller can provide an indication of a first leak in the seal.
