Water Treatment. Even though hot water systems are “closed”, some amount of make-up water (up to 10%) will be introduced, usually due to pump seal leaks or other minimal leaks from valves etc., that go unnoticed. therefore, proper water chemistry of a hot water boiler is necessary for good operation and longevity, particularly to ensure that free oxygen is removed to prevent waterside corrosion. For steam boilers, proper blowdown (surface and bottom) is a required maintenance procedure. This water loss and associated steam use or loss must be made up. Any make-up water should be properly treated prior to introduction into the boiler via water softener, chemical feed, etc. Proper water chemistry in a steam boiler is mandatory for effective operation and longevity.  The photo above shows dark areas where the shell was eaten through and started to drip water.  The boiler failed far short of expected life. 

Electric Boilers Water Quality:  Local water and boiler experts should verify best treatment.

Hot Water and Steam values.

pH  8.3 - 9.5 , 8.3 - 10.5 

Iron 0.1 ppm 0.1 ppm 

Alkalinity <300 ppm <600 ppm 

Chlorides 30 mg/liter 30 mg/liter 

Oxygen 0.1 mg/liter 0.1 mg/liter 

Specific Conductivity 3500 mmho/cm 4500 mmho/cm 

Total Hardness <3 ppm <3 ppm

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