Table of Contents
Advertisement
Make-up water is needed to supplement splash loss of the cooling water in the cooling tower
and besides the blow-down of cooling water is also needed to prevent condensation due to
evaporation. In order to determine the volume of blow-down, increase the volume gradually to
maintain the target water quality according to the inspection result of cooling water quality
during operation, and determine the blow-down volume.
As for water quality control and water treatment, contact our service agent
9.4.3 Control of chilled water and hot water line and cooling water line during prolonged shut-down.
When the chiller-heater is shut-down for a long period, be sure to control the chilled and hot water
line and cooling water as per the following procedure.
(1) Chilled and hot water control
1) Leave the chilled/hot water to be filled with in the chiller-heater.
2) During the shut-down period periodical circulation of the chilled/hot water by the pump is
recommended. This is for equalization of the density of chemicals in the chilled/hot water.
(2) Cooling water control
Regularly, the cooling water is left to be filled with in the chiller-heater. But in case there is a
possibility of freezing in winter, leave it to be drained and kept dry.
In case of leaving the cooling water to be filled with>
1) Leave the cooling water line to be filled with in the chiller-heater.
2) During the shut-down period perform the water quality analysis periodically to check if the
water quality standard of cooling water (See Table 9.3) is satisfied.
3) When it is found to be out of the water quality standard, perform a proper water treatment
such as chemical treatment.
4) During the shut-down period periodical circulation of the cooling water by the pump is
recommended. This is for equalization of the density of chemicals in the cooling water.
<In case of leaving the cooling water line to be drained and kept dry>
1) Open the drain valve for cooling water to drain the cooling water from the cooling water line.
(Open the purge valve also at the same time.)
2) Leave both the drain valve and the purge valve open during the shut-down period.
(3) Chilled/hot water line in winter
When there is a possibility that the ambient temperature of the chiller-heater goes down below
0 ℃ during the shut-down period, it is necessary to take some protective measure for freezing
on the chilled/hot water line. In such case, contact our service agent.
9.5 Inspection and Cleaning of Tubes
The deposition of scales on the tube walls may lower the heat-exchange efficiency resulting in the
drop of capacity drop. Therefore, be sure to remove the scale deposits by mechanical or chemical
cleaning as per the following procedure, according as the situations. Needless to say, it is essential
to perform not only a regular cleaning once a year but also timely and temporary cleaning
depending on the state of scale deposits. Especially, in the initial period of operation of the chiller-
heater, it is desirable to perform tube cleaning once a week, and then once a month, extending the
interval gradually, because dusts and foreign matters are likely to be deposited in the piping in the
period. If the contamination is heavy, check the water quality, and treat the water chemically.
Scale deposit is detected by the following signs.
(1) Decrease in capacity
(2) Abnormal rise in the temperature of the condensed refrigerant entering from the condenser to
the evaporator during operation.
(3) Abnormal decrease in the temperature of the cooling water flowing from the outlet of the chiller-
51
Advertisement
Table of Contents
