Systems and methods for detecting a leak in a heat exchanger of a hemodialysis device may include opening a drain valve disposed in a spent dialysate circuit, and then closing the drain valve after a pre-selected time period, determining an initial pressure in the spent dialysate circuit and storing the initial pressure in the memory, sensing a system pressure at periodic time intervals and comparing to a pre-determined maximum pressure, and determining whether the heat exchanger has a leak, in that in response to the system pressure exceeding a predetermined maximum pressure, a command may be generated to execute an event including suspending a disinfectant operation with a disinfecting agent, and in response to the initial pressure subtracted from the system pressure being greater than a predetermined minimum pressure differential, a command may be generated to execute an event including suspending the cleanse operation with the disinfecting agent.
