PH value of boiler water and feedwater should be maintained. Corrosive qualities of water can be known from PH value because it indicates that quality of water is alkaline, neutral or acidic. But PH value does not show about amount of quantity of alkaline or acidic content in water.
PH value has range between 0 until 14. If PH value is in the middle value (PH 7) so the quality of water is neutral. If PH value fewer than 7 (PH 0-6) so the quality of water is acidic, but on contrary PH value above 7 so the quality of water is alkaline. PH value also states concentration of hydrogen ions and hydroxide ions. Hydrogen ions will dominant in acidic water and hydroxide ions will dominant in alkaline water.
Requirement PH value for boiler water and feedwater is generally above 7 (range between 8.5 and 9.8). It is recommended PH value to protect metal pressure part from corrosion attack. The following figure below is the recommended material construction of steam boiler based on PH velue.