Boiler water test
Because of the inherent difficulties involved in any attempt at
automatic control of feed water treatment, it is necessary that the exact
condition of the boiler water be known from day to day, in order that necessary
treatment can be applied for the correction of any unsatisfactory conditions
which may exist.
|Table 1 - Recommended boiler water characteristics|
|Boiler pressure bar||pH||Alkalinity to Penolphtalein
|Chlorides max ppm CI||Phosphate
|Dissolved solids ppm|| Sulphite or Hydrazine excess
|1 To convert from Chioride as ppm CaCO3 to ppmNaCl,
multiply by 1.17.
2 To convert from Chloride as ppm CaCO3 to ppm Cl, muitiply by 0.7 1.
3 To convert from Alkalinity as ppm CaCO3 to ppm NaOH, muitiply by 0.8.
4 To convert from Phosphate as ppm P04 to ppm P2O5, muitiply by 0.75.
|Table II - Recommended feed water characteristics|
|Boiler pressure bar||Chioride max ppm Cl||pH||Dissolved O2 max mi/litre|
|Residual hardness in F.W.T. max 0. 1°dH.
1 To convert from Chioride as ppm CaCO3 to ppm NaCI, multiply by 1.17.
2 To convert from Chioride as ppm CaCO3 to ppm Cl, multiply by 0.7 1.
3 To convert from Oxygen from ml/litre O2 to ppm (weight for weight) O2, multiply by 1.5.
HARDNESSA water with higher content of Caicium or Magnesium salts feels "harder" when washing with soap than water with lower content of same. Hardness is normaily measured in °dH (German degree of hardness). 1 °dH correspond to 10 ppm of CaO or equivalent 7.8 ppm MgO.
Due to make of treatment used, there are several kinds of test kits available, each one corresponding to the test log sheets in order to get the treatment company's opinion.
DRAWING SAMPLES for a BOILER WATER TESTAlways remember that the chemical analysis can never be more accurate than the sample. The sample must be truly representative of the water in the boiler.
The sampling connection to the boiler shall be shortest possible and well cooled. Sampling lines should be flushed thoroughly by allowing the water to run trough for at last half a minute. All equipment to be kept scrupulously clean and rinsed four times with sample water before the sample is measured out.