SECTION 4 4500P-7500 USER MANUAL
51
2. Remove the drain plugs that are located at
the bottom of the aftercooler and the lubri-
cant cooler end caps.
3. Allow the system to drain completely.
WATER QUALITY RECOMMENDATIONS
Water quality can significantly effect the efficiency of
the water cooling system. Dissolved minerals, gases,
and pH values are factors that contribute to the
formation of deposits and corrosion which can form
on the interior of cooling system pipes and heat
exchangers.
Scale can be a problem if the water supply has a
high concentration of calcium carbonate. It forms
lime scale deposits which act as thermal insulators
and restrict the water flow through the cooling
system. If scale is allowed to build up over time, it will
reduce the system’s ability to remove heat and the
compressor can be damaged. Scale buildup can be
controlled with proper water treatment.
Corrosion damages pipes and reduces their strength.
This type of damage is more likely if the water supply
NOTE
In some cases a thin lime scale coating can
inhibit corrosion.
Table 4-2: Ventilation Requirements
Cooling Type Air-Cooled with Aftercooler
Water-Cooled
Motor HP/KW
60 / 45 75 / 55 100 / 75 60 / 45 75 / 55 100 / 75
Fan Air cfm/m
3
/hr
7,300 / 12,400 7,300 / 12,400 8,100 / 13,800 2,845 / 4,835 2,845 / 4,835 2,845 / 4,835
Ventilating Air/
Heat Rejection
BTU/hr
170,300 213,000 286,000 16,000 20,000 26,800
KCal/hr 46,000 57,500 77,300 4,300 5,400 7,200
Cooling Water/
Heat Rejection
BTU/hr
170,300 213,000 286,000
KCal/hr 46,000 57,500 77,300
Table 4-3: Water Tests
Substances Test Interval Acceptable Concentration
Corrosivity Hardness, pH, Total
Dissolved Solids, Temperature at inlet,
Alkalinity
Monthly - if stable for 3 to 4 months,
analyze quarterly.
Langelier Index 0 to 1
Iron Monthly < 2 ppm
Sulphate Monthly < 50 ppm
Chloride Monthly < 50 ppm
Nitrate Monthly < 2 ppm
Silica Monthly < 100 ppm
Desolated Oxygen Daily - if stable, analyze weekly 0 ppm (as low as possible)
Oil & Grease Monthly < 5 ppm
Ammonia Monthly < 1 ppm
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