System and method for cleaning stator cooling coils

Methods and systems are disclosed for removing cuprous oxide deposits from a copper-containing water-based cooling system, such as those used to cool stators in industrial generators, without disrupting operation of the cooling system. A complexing agent, such as a 1,10-phenanthroline, e.g., 2,9-dimethyl-1,10-phenanthroline (neocuproine), a 2,2-bipyridine compound, or the like can be introduced into the coolant fluid to facilitate dissolution of the deposits by forming a complex with the cuprous ions. The complexing agent can be dissolved in an alcohol at a concentration of about 4-5%, and then added to the coolant fluid to a concentration of about 6e-3 M or less to avoid undesirable precipitation of the agent. The complexing agent can be recovered by flowing the coolant mixture through an adsorbent material such as activated carbon, and the copper can be removed from the agent by reacting it with sodium sulfide.