In some embodiments, an apparatus for providing negative pressure wound therapy to multiple wounds includes a negative pressure source configured to couple via a plurality of fluid flow paths to a plurality of wound dressings. The plurality of flow paths includes a plurality of calibrated leaks. The apparatus also includes a controller configured to determine a total rate of flow in the plurality of fluid flow paths and compare the total rate of flow to a plurality of thresholds associated with the plurality of calibrated leaks to determine one or more operating conditions, such as a blockage in one or more of the plurality of flow paths. An indication of the operating condition can be provided.