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Water quality standards for heat exchangers

Water quality standards for cooling water for heat exchanger Make sure to use the water quality criteria shown on the list below for the heat exchanger cooling water.

  Item Standard
  Corrosion Scale
Standard items pH[25Ž] 6.5`8.2 › ›
Conductivity[25Ž](ms/m) 80 and below › ›
Iron Chloride(mgCl-/L) 200 and below ›  
Iron Sulfate(/L) 200 and below ›  
Acid Consumption[pH4.8](mgCaCo3/L) 100 and below   ›
Total hardness(mgCaCo3/L) 200 and below   ›
Calcium hardness(mgCaCO3/L) 150 and below   ›
Ionic Silica SiO2(mgSiO2/L) 50 and below   ›
Ref items Fe(mgFe/litter) 1.0 and below › ›
Cu(mgCu/L) 0.3 and below ›  
Iron Sulfide(mgS2-/L) Not detected ›  
Iron Ammonium(/L) 1.0 and below ›  
Residual chlorine(mgCl/L) 0.3 and below ›  
Free carbon dioxide(mgCO2/L) 4.0 and below ›  
Ryznar stablity index(R.S.I) 6.0`7.0 ›  

From the Japan Refrigeration and Air Conditioning Industry Association Standards (JRA-GL-02-1994)


In general, it is assumed that tap water, underground water, and industrial water are used as cooling water. Be aware of the possibility of contamination if untreated water such as water from rivers, lakes, and ponds is used.


These standards extend the service life and maintain the efficiency of the heat exchanger. Also, control values are established to prevent the decrease of these and corrosion may occur even under the standard values.