Regarding Water Quality Standards

About Chilled Water

Standard for Usable Chilled Water

The recommended liquid for use in a chiller (chilled water) is clean water (see the water standard chart below), or a 30% to 40% solution industrial-use ethylene glycol. Note that if a 30% to 40% solution of industrial-use ethylene glycol is used, then there will be a reduction in cooling capacity of 10%. Alternatively, if conditioned water is used, then it should have an electrical conductivity of at least 1 µ/cm. Use of other than designated liquids can lead to product damage, liquid leakage, electrical shocks, or electrical shorts.

Standard Value
Standard Item PH(25℃) 6.8 to 8.0
Conductivity (µS/cm) (25 °C) 1 to 400
Chloride Ion (mgCI-/L) 50 or lower
Sulphate (mgSO42-/L) 50 or lower
Acid Consumption (pH 4.8) (mgCaCO3/L) 50 or lower
Total Hardness (mgCaCO3/L) 70 or lower
Calcium Hardness (mgCaCO3/L) 50 or lower
Silica Ion (mgSiO2/L) 30 or lower
Reference Components Iron (mgFe/L) 1.0 or lower
Copper (mgCu/L) 1.0 or lower
Sulfide Ion (mgS2-/L) Not detected
Ammonium Ion (mgNH4+/L) 1.0 or lower
Residual Chlorine (mgCI/L) 0.3 or lower
Free Carbon Dioxide (mgCO2/L) 4.0 or lower
  • Excerpt from JRA-GL-02-1994 of The Japan Refrigeration and Air Conditioning Industry Association

About Cooling Water

Cooling Water Choices

While underground water, tap water, or cooling towers are generally thought of as sources of cooling water for water-cooled condensers, the water quality standards listed below should be carefully considered when choosing the water source.

Water Quality Standard Guidelines

The following water quality standard should be used as a guideline for primary cooling water (water for water cooled condensers in refrigeration equipment, constant-temperature circulating water in water temperature controllers, or conditioned water used for heating).

Water Quality Standard for Primary Cooling Water

  1. If tap water is used as the primary cooling water for water cooled equipment, then the water should meet the following water quality standard.
  2. Within the "Tendency toward" column, items marked with a ○ indicate this component can lead to corrosion or scaling as indicated.
  3. The 15 items listed below are the primary components that can lead to corrosion or scaling.
Item Cooling Water System Has Tendency Towards:
Circulating water Make-up Water Corrosion Scaling
Standard Item PH(25℃) 6.5 - 8.2 6.0 - 8.0
Conductivity (µS/cm) (25 °C) 800 or lower 300 or lower
Chloride Ion (mgCI-/L) 200 or lower 50 or lower  
Sulphate (mgSO42-/L) 200 or lower 50 or lower  
Acid Consumption (pH 4.8) (mgCaCO3/L) 100 or lower 50 or lower  
Total Hardness (mgCaCO3/L) 200 or lower 70 or lower  
Calcium Hardness (mgCaCO3/L) 150 or lower 50 or lower  
Silica Ion (mgSiO2/L) 50 or lower 30 or lower  
Reference Components Iron (mgFe/L) 1.0 or lower 0.3 or lower
Copper (mgCu/L) 0.3 or lower 0.1 or lower  
Sulfide Ion (mgS2-/L) Not detected Not detected  
Ammonium Ion (mgNH4+/L) 1.0 or lower 0.1 or lower  
Residual Chlorine (mgCI/L) 0.3 or lower 0.3 or lower  
Free Carbon Dioxide (mgCO2/L) 4.0 or lower 4.0 or lower  
Ryznar Stability Index 6.0 to 7.0 -