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Boiler Water Quality

Boiler Chemicals are used to ensure proper Boiler Water Quality in boilers.

The below table is the Total Dissolved Solids or TDS, Alkalinity, and Hardness versus Boiler Pressure.

First, knowing the water source is important, whether it is from ponds, rivers, ground wells, or city water. It is essential in determining the type of boiler water treatment chemicals needed. Each water supply source requires a specific analysis for larger more complex steam boiler systems. In 95% of all boiler applications, companies use good softened city water.  This is the good start for good Boiler Water Quality.

To start, minerals dissolve in water and ions are formed. The total of all water ions is referred to as the total dissolved solids or TDS.

Iron may be soluble or insoluble. Insoluble and soluble iron may block valves and strainers which can lead to boiler process problems and ultimate premature boiler failure.

Water Hardness is the measure of the amount of calcium and magnesium in the water. Water Hardness is the primary source of scale in boiler equipment. Always use a softener to ensure good Boiler Water Quality. Chemicals are designed to polish away small amounts of hardness that by-passes the softener.

Silica in boiler feedwater can be a problem in larger steam boiler systems.  You must maintain a Total OH alkalinity ratio of 3:1 in high pressure boilers to prevent plating of silica.

Alkalinity is a measure of the capacity of water to neutralize strong acids.  Alkalinity also increase the water pH to reduce the overall corrosion rates on steel and alkalinity keeps your polymer working to prevent scaling.

Alkalinity may also contributes to foaming and carryover in boilers. See the below chart for standard good Boiler Water Quality.

 Boiler Stem Pressure (psi)
 Maximum TDS (ppm)
 Maximum Alkalinity (ppm)
 Maximum Hardness (ppm)
 Low - 300
 700 <20
 301 - 450
 3000 600 0
 451 - 600
 2500 500 0
 601 - 750
 751 - 900
 1500 300 0
 901 - 1000
 1250 250 0
 1001 - 1500
 1000 200 0
 1501 - 2000
 750 150 0
 2001 -3000

For more information, please contact us at 800-658-7716 or email our sales consultant at JZajac@ChemWorld.com.