In some embodiments, a negative pressure wound therapy device includes a negative pressure source and a controller configured to, in response to determining that the negative pressure source is directly fluidically connected to a wound dressing without a canister between the two, operate the negative pressure source in a first mode; otherwise, operate the negative pressure source in a second, different mode. The controller can be further configured to, in response to determining that a level of activity of the negative pressure source over a first time duration satisfies at least one of a leak or blockage condition, provide an indication of at least one of a leak or blockage and, in response to determining that the level of activity does not satisfy the at least one of the leak or blockage condition over a second time duration subsequent to the first time duration, discontinue providing the indication.