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13-21-615 v01 Page 65
It is mandatory that any water-cooled unit be installed in a shelter heated to
temperatures above freezing (32
F, 0
C).
Oil cooler malfunction may be traced by checking pressure at oil inlet and outlet. At normal operating air
service pressure (65 psig to 150 psig, 4.5 bar to 10.3 bar) with the unit warm, a pressure drop of 20 psi to
35 psi (1.38 bar to 2.41 bar) can be expected between the oil inlet and the oil outlet.
Water pressure drop from water inlet to outlet will vary with the inlet pressure and amount of water flowing.
A normal pressure drop may range from 5 psi to 10 psi (.3 bar to .7 bar). Any change in the pressure drop
from that normally held may indicate tube leakage or fouling and should be investigated.
In many instances, the cooling water supply for the heat exchanger will contain impurities in solution and/or
suspension. These substances can cause scale formation, corrosion and plugging of any water-cooled
heat exchanger equipment. Disregarding the possibility that one or more of these conditions exist may
result in increased maintenance and operation expense, reduced equipment life and emergency shutdown.
It is strongly recommended that a reputable, local water treatment concern be engaged to establish the
corrosion, scale forming and fouling tendency of the cooling water and take steps necessary to remedy the
situation if a problem does exist. The need for water treatment may involve only filtration (screening) to
remove debris, sand and/or salt in the cooling water supply. However, chemical treatment methods may
be necessary in certain instances to inhibit corrosion and/or remove di
ssolved solids, to alter the water’s
tendency to form scale deposits, or prevent the growth of microorganisms. The normal maintenance
program for the unit should also include periodic cleaning of the tubes (water side) of the heat exchanger
to remove deposits which enhance fouling and corrosion.
Figure 5-10 WATER CONTROL VALVE