The hardness of water is caused by calcium and magnesium ions which will vary greatly throughout the country depending on the source.
Boiler water hardness ppm.
It is desirable to keep the concentration of phosphates in the water to 30 50 ppm in order for complete reaction of the phosphates with the calcium hardness entering the boiler through the feedwater.
Scale is a buildup of solid material formed on internal boiler surfaces.
For boiler water however a hydrometer can be used to obtain an approximate measurement of the dissolved solids since for boiler water each increase of 0 000 1 relative density at 15 5 c is approximately equal to 110 ppm.
Ph 8 3 10 0.
Total alkalinity 700 ppm.
Most boiler systems have sodium zeolite softened or demineralized makeup water.
Specific conductance 7000 umhos.
Total hardness 0 3 ppm.
Feedwater hardness usually ranges from 0 01 to 2 0 ppm but even water of this purity does not provide deposit free operation.
In addition hardness salts can precipitate from the boiler water to form sludge and eventually scale which deposits on the internal surfaces of the boiler.
The below table is the total dissolved solids or tds alkalinity and hardness versus boiler pressure.
Total silica 150 ppm maximum.
Non volatile toc 1 ppm.
Total alkalinity 600 ppm maximum.
Total hardness 1 ppm maximum.
First knowing the water source is important whether it is from ponds rivers ground wells or city water.
Water treatment recommendations vary depending on the operating pressure of the boiler the application steam or hot water and other parameters.
In treated waters alkalinity may also be contributed by hydroxide phosphate silicate and.
Free oh alkalinity 200 400 ppm.
Alkalinity test in natural waters alkalinity is most commonly the result of bicarbonate and carbonate ions.
A serious loss of boiler efficiency and possibly boiler failure.
A low pressure fire tube boiler can usually tolerate high feed water hardness with proper treatment while virtually all impurities must be removed from water used in some modern high pressure boilers.
Therefore good internal boiler water treatment programs are necessary.
Boiler water quality boiler chemicals are used to ensure proper boiler water quality in boilers.
Feed water purity requirements therefore can vary widely.
General guidelines to prevent corrosion and scaling in low pressure boilers are as follows.
Only relatively wide ranges can be given as to maximum levels of alkalis salt silica.
