Table 32: Chilled water and cooling water quality control (maximum concentrations)
Cooling water system
(3) (4)
Circulating type
Non-
circulating
water
Chilled water system
(3)
Tendency
(2)
Element
(1) (6)
Circulating
water
Replenish
water
(5)
Passing
water
Circulating
water (20 °C
or lower)
Replenish
water
(5)
Corrosion
Scale
forming
PH (25°C) 6.5~8.2 6.0~8.0 6.8~8.0 6.8~8.0 6.8~8.0 X X
Electric Conductivity
(mS/m) (77°F)
(µS/cm) (77°F)
(1)
Max 80
(Max 800)
Max 30
(Max 300)
Max 40
(Max 400)
Max 40
(Max 400)
Max 30
(Max 300)
X X
Chloride Ion (MgCl
-
/L)
Max 200 Max 50 Max 50 Max 50 Max 50 X
Sulfulic Acid Ion
(mgSO
4
2-
/I)
Max 200 Max 50 Max 50 Max 50 Max 50 X
Acid Consumption
(PH4.8) (mgCaCO
3
/I)
Max 100 Max 50 Max 50 Max 50 Max 50 X
Total Hardness
(mgCaCO
3
/I)
Max 200 Max 70 Max 70 Max 70 Max 70 X
Calcium Hardness
(mgCaCO
3
/I)
Max 150 Max 50 Max 50 Max 50 Max 50 X
Standard
items
Ionized Silica (mgS
1
O
3
/I)
Max 50 Max 30 Max 30 Max 30 Max 30 X
Iron (mgFe/I) Max 1.0 Max 0.3 Max 1.0 Max 1.0 Max 0.3 X X
Copper (mgCu/I) Max 0.3 Max 0.1 Max 0.1 Max 0.1 Max 0.1 X
Sulfurization Ion
(mgS
2-
/I)
No ions allowed X
Ammonium Ion
(mgNH
4
+/I)
Max 1.0 Max 0.1 Max 1.0 Max 1.0 Max 0.1 X
Residual Chlorine
(mgCI/I)
Max 0.3 Max 0.3 Max 0.3 Max 0.3 Max 0.3 X
Free Carbonate Acid
(mgCO
2
/I)
Max 4.0 Max 4.0 Max 4.0 Max 4.0 Max 4.0 X
Reference
items
Stability Index 6.0~7.0 - - - - X X
Note:
1. Names and units are according to JIS K 0101-91. The units and figures in braces are no
longer used. They are shown for reference.
2. The X in the Tendency column indicates that the item is a factor in corrosion/scale
formation.
3. When the water temperature is 104°F or higher, corrosion develops. If the steel in direct
contact with water has no protective coating, add a corrosion-prevention agent or
perform deaeration treatment.
4. In a cooling water system that uses a closed cooling tower, the closed-circuit circulating
water and its replenishment water must meet the quality standards for a hot water
system. The sprinkling water and its replenishment water must meet the quality
standards for a circulation-type cooling water system.
5. The supply water and the replenishment water must be tap water, industrial water, or
ground water. Do not use demineralized water, neutral water, or softened water.
YHAU-C Single Effect Steam-Fired Absorption Chiller162
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