PURGE REQUIREMENTS
The installer of BAC closed circuit cooling towers must ensure a proper air purging of the system prior to operation.
Entrained air can restrict the capacity of the cooler, resulting in higher process temperatures.
All connections (installed by others) must be leak free and tested accordingly.
CIRCULATING WATER QUALITY
The standard heat exchanger coils are made of black steel and are galvanized on the outside only. They are
intended for application on closed, pressurized systems which are not open to the atmosphere in order to prevent
internal corrosion of the coil and possible leaks.
The circulating water quality needs to remain within the following limits:
pH
7 - 10.5
Hardness (as CaCO3)
100 - 500 mg/l
Alkalinity (as CaCO3)
100 - 500 mg/l
Conductivity
< 3000 µS/cm
Chlorides
< 200 mg/l
Total suspended solids
< 10 mg/l
COD
< 50 ppm
Above values are general guidelines for pressurized closed systems closed systems with a leak rate lower than
15% of system volume per year. If the annual make-up of the closed system is greater than 15% yearly or if highly
corrosive water such as water with very low hardness or alkalinity is used, it is recommended to consider
alternative stainless steel material or implement a proper water treatment program to prevent steel corrosion.
Stainless steel coil are available to cool corrosive fluids or water and ethylene/propylene glycol solutions in
systems open to the atmosphere. In case of stainless steel heat exchanger coils the circulating water quality
needs to remain within the following limits:
SST304L
SST316L
pH
6.5 - 10.5
6.5 - 10.5
Hardness (as CaCO3)
0 - 500 mg/l
0 - 500 mg/l
Alkalinity (as CaCO3)
0 - 500 mg/l
0 - 500 mg/l
Conductivity
< 3300 µS/cm
< 4000 µS/cm
Chlorides
< 250 mg/l
< 750 mg/l
Total suspended solids
< 10 mg/l
< 10 mg/l
COD
< 50 ppm
< 50 ppm
In all cases, regardless of the material of construction of the coil a competent water treatment company should be
consulted for the specific water treatment to be applied, suitable for all the materials of construction used in the
entire system.
W W W . B A L T I M O R E A I R C O I L . E U
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2 General information
2 General information