Errata to the article by [Al Ismaili, R., Lee, M., Wilson, D., Vassiliadis, V., 2018. Heat exchanger network cleaning scheduling: From optimal control to mixed-integer decision making. Computers & Chemical Engineering 111, 1–15.] on the optimal scheduling of cleaning actions for Heat Exchanger Networks subject to fouling are presented. Errors present in the equations of the Pontryagin Minimum Principle analysis of the original article are indicated and rectified. It is noted that despite these errors, there is no change to the conclusions of the analysis given in [Al Ismaili, R., Lee, M., Wilson, D., Vassiliadis, V., 2018. Heat exchanger network cleaning scheduling: From optimal control to mixed-integer decision making. Computers & Chemical Engineering 111, 1–15.].