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7. MAINTENANCE
ENGLISH
Yearly inspection
Classification
Inspection item
Inspection method
Standard
Compressor
Compressor motor
connector locking
bolt
Check for loosening
Whether loosened or not
Terminal treatment condition
Condenser
Chemical analysis
Water quality analysis
Water quality standard
Tube status
Check with daily operation record
or opening water box(water room)
There should be no contamination.
Evaporator
Chemical analysis
Water quality analysis
Water quality standard
Tube status
Check with daily operation record
or opening water box(water room)
There should be no contamination.
Oil and
lubricant
Ejector cleaning
Disassemble and clean
There should be no problem.
Filter cleaning
Filter change, housing cleaning
There should be no problem.
Oil change
2000 hours or 1 year
Figure 63 Yearly inspection standard
<Water quality analysis>
The cooling water of the open circulation type cooling tower is re-used after dropping the water temperature using
the latent heat of vaporization.
At this time, as the water vaporizes, the amount of chloride ion, acid ion, etc. increases in the water.
That is, the enrichment of ions in the cooling water gradually deteriorates the water quality.
Also, in the cooling tower, water and air are always in contact each other, and the pollutants(automobile exhaust gas,
sulfurous acid gas, dust, gases from chemical plants such as ammonia or petroleum gas, etc.) deteriorate the water
quality even more.
Corrosion on the copper pipe or scale attachment caused by the contamination of the cooling water makes holes in
the tube, or blocks copper tube, or makes heat exchange capacity drop.
This causes the tube to be changed, power cost to increase, or chiller to be broken down. Therefore it is necessary
to maintain the cooling water quality adequately.
Carry out periodical water quality analysis, and if it exceeds the water quality standard, it should be changed. In the
beginning of the season or when the chiller is installed and operated for the first time, water quality analysis should
be conducted.
To prevent the concentration of the cooling water, drain a certain amount during the cooling water circulation. Supply-
ing new cooling water is another method, and the water quality can also be managed by chemical treatment method.
<Tube condition>
If water scale is incrusted in the inner wall of the tube, or foreign object enters blocking the tube, the heat resistance
will increase decreasing the refrigerating capability. Be careful of this.
If hard foreign objects such as sand enter the cooling water, erosion or corrosion may occur in the inlet/outlet area of
the tube, therefore make sure to check the inner wall of the tube during the tube cleaning.
Install filter at the inlet of the cooling water pipe.
Cooling water system usually comes with cooling tower, but different from this, underground water or stream water
may be used. In this case, water quality is low, and there are many cases of having scales attached, in contrast to the
chilled water side.
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