In some cases it may be necessary to condition the heating water. The German VDI guideline 2035 states: “In the case of aluminium materials in the system, further measures (e.g. dosing of inhibitors) may be necessary to prevent corrosion both during softening and desalination”.
According to the guideline, corrosion protection by means of inhibitors is even necessary in case of constant, unavoidable oxygen entry (German VDI guideline 2035, Section 8.4.3).