- to react with incoming feedwater hardness and prevent it from precipitating on the boiler metal as scale
- to condition any suspended matter such as hardness sludge in the boiler and make it nonadherent to the boiler metal
- to control the causes of boiler water carryover
- to eliminate oxygen from the feedwater
- to provide enough alkalinity to prevent boiler corrosion
In addition, a complete treatment program should prevent corrosion and scaling of the feedwater system and protect against corrosion in the steam-condensate systems.