84 CGWF-SVX01A-EN
Unit Maintenance
• Inspect evaporator and condenser tubes and clean, if needed.
• Clean and repaint any corroded surface.
• Inspect the expansion valve sensing bulbs for cleanliness. Clean if required.
Sensing bulbs must make good contact with suction lines and be properly insu-
lated.
• Clean remote condenser coils (CCAF only). Refer to the condenser manufac-
turer's recommendations.
Maintenance Procedures
This section describes specific maintenance procedures which must be performed as
a part of the normal maintenance program for this unit. Be certain that electrical
power to the unit is disconnected before performing these procedures.
Cleaning the Condenser (CGWF Units Only)
Water available for condensing frequently contains minerals or other contaminants
that collect on the inside of the condenser tubes as carbonate scale. Scale accumula-
tion will accelerate with high condensing temperatures and use of water with high
mineral content. Cooling towers collect dust and foreign material which also deposits
on the condenser tubes, forming sludge.
To maintain maximum efficiency, the condenser must remain as free of these depos-
its as possible. Even a very thin layer on the inside tube surfaces reduces the heat
transfer ability of the condenser. Indications of scale deposits are decreased water
flow through condenser, reduced temperature differential between entering and leav-
ing condensing water and abnormally high condensing temperatures.
These are two accepted methods of cleaning condenser tubes. They are mechanical
cleaning and chemical cleaning.
Mechanical Cleaning
The mechanical cleaning method is used primarily to remove sludge and other loose
material from the condenser tubes. Use the following procedure.
1. Turn off chiller and condenser water supply.
2. Break piping connections at the unions.
3. Remove the condenser heads.
4. Run a round nylon brush from end to end through the tubes to loosen deposits.
5. Flush the tubes with water. Then inspect tubes for scale accumulation. If there is
no scale in the tubes reassemble condenser and piping.
6. If there is scale in the tubes, proceed with the chemical cleaning procedure.
Chemical Cleaning
Chemical cleaning is the most satisfactory method of cleaning scale from condenser
tubes. With this treatment, scale is dissolved and flushed away by circulating a chem-
ical solution through the tubes and headers.
Internal condenser components are composed of copper, steel and cast iron. With
this information, water treatment firms will be able to recommend a suitable chemical
for this purpose. If water treatment is not available, consult a chemical supply house.
Cleaning the Evaporator (Chiller)
The evaporator water system is part of a closed loop and should not accumulate an
appreciable amount of scale or sludge. If it is determined that the chiller is fouled,
first attempt to dislodge any foreign material by back flushing the system several
times. If this does not work satisfactorily, chemically clean the chiller using the proce-
dures outlined in "Chemical Cleaning" for the condenser.
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