- Refrigerant charging amount adjustment
To enhance the performance of the machine, if it is required to adjust the refrigerant filling amount, operate the ma-
chine in the designed load, and slowly add or remove refrigerant until the difference of the chilled water outlet
temp. and vaporizer refrigerant temp. becomes the designed condition or minimum. Do not over fill. Refrigerant
can be added through storage tank or it may be directly filled into the chiller.
- Refrigerant leakage inspection
HFC-134a has higher pressure than air pressure in room temperature, so leakage inspection is necessary, and carry
out the leakage inspection with electronic detector, halogen leakage detector, or soap bubbles. Room ventilation
shall be good, and to prevent wrong measurement, check if the refrigerant is concentrated in one place. Before
performing any repair for leakage, remove all the refrigerant from the leaked container.
- Refrigerant leakage
If there is a lot of refrigerant leakage and chiller performance is greatly degraded and operation becomes impossible,
stop the use of the chiller and repair is recommended.
- Refrigerant filter
Refrigerant filter/drier in the refrigerant cooling pipe of the motor needs to be replaced once a year, and it may re-
quire more frequent replacement according to the status of the filter.
To find the existence of moisture in the refrigerant, site glass is installed next to the filter.
If you see moisture through the site glass, perform a thorough leakage inspection to find the source of the water.
Heat exchanger pipe cleaning (vaporizer/condenser)
Heat exchanger tube inspection
- Evaporator
When the first operation season is over, clean the vaporizer tubes. These tubes have foreign objects inside, so to
completely clean the tubes, it requires a special caution. The tube condition at this time will become the data to de-
cide how often tube needs to be cleaned and whether water handling in the chilled water(brine) system is appropri-
ate.
Check the corrosion or scale in the chilled water inlet/outlet temp. sensor, and if there is a corrosion, replace the
sensor, and if there is a scale, remove the scale.
- Condenser
Coolant circuit is generally an open type system, so it is easy to have the tubes contaminated and scale to be accu-
mulated. Therefore, condenser tubes need to be cleaned at least once a year, and if the water quality is contami-
nated, clean more frequently.
Check the corrosion or scale in the coolant inlet/outlet temp. sensor, and if there is a corrosion, replace the sensor,
and if there is a scale, remove the scale.
The reason that it is higher than the normal condenser pressure and not reaching previous chilling load is generally
because tube is contaminated or there is an air in the machine.
If the difference between coolant outlet temp. and condenser refrigerant temp. is big, condenser tube may be con-
taminated or water flow is not good. HFC-134a is a high pressure refrigerant, so it is easier to have refrigerant leak-
age than having air inside.
During the cleaning of the tube, use a specially designed brush to prevent scratch on the tube wall. Never use wire
brush.
!
CAUTION
To prevent severe scale and removal of the scale, treat with chemical, but for proper treatment, consult with water treat-
ment specialist.
7. MAINTENANCE
102
ENGLISH
Summary of Contents for LCWW
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