In order to make efficient use of the steam condensate of system, a mixed ion exchanger was added to the desalted water unit, and the condensate was treated with ion exchange to produce refined water for external supply. After the new mixed ion exchanger was put into use, problems such as resin loss and pipeline blockage appeared successively. In order to ensure the efficient recovery of condensate, the faults were checked during several maintenance and the causes were analyzed item by item. Some treatment methods were put forward, and the faults were treated correspondingly. The results show that the reasonable modification of the internals of mixed ion exchanger can effectively prevent the resin from blocking the pipe and from running away, so as to ensure the long-term and stable operation of the ion exchanger.