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183
18.1.4 Specifications
18.1.4.1 Specifications of fresh water was heat transfer medium in brazed heat
exchanger
Parameter
Quality Limits for Tap Water on the Secondary Side
Temperature Below
60°C
pH
7 to 9
Alkalinity
60mg/l < HCO
₃
< 300mg/l
Conductivity <
500
μ
S/cm
Hardness [Ca
⁺
, Mg
⁺
] / [HCO
₃⁻
] > 0.5
Chloride
< 200mg/l at 60°C
Sulphate [SO
₄
²
⁻
] < 100mg/l and [HCO
₃⁻
] / [SO
₄
²
⁻
] > 1
Nitrate
NO
₃
< 100mg/l
Chlorine <
0.5mg/l
18.1.4.2 External
filter
Solids in the water must be filtered.
Minimum filter mesh size required for the field supply external filter in the water inlet is 20 mesh.