Due to excessive residual chlorine, resin oxidation and water production of 18 ionsure lxm45z EDI units in a thermal power plant of Huaneng Group decreased. After maintenance by Shenzhen Enrico company, the data of a single set: water quality 0.057 µ, water volume 5m3/h, current 3a, voltage 90V, silicon dioxide 5.2ppb, all data meet the new EDI standard, and the acceptance is successful.