13
FAN
–Inspect fan blade surfaces every six months. For detailed maintenance informa-
tion, refer to the Fan User Manual.
GEAREDUCER
–Make weekly and monthly oil checks. Inspect internal parts during
seasonal oil change. Refer to the Geareducer User Manual
for detailed maintenance
instructions.
DRY DAMPERS
–Inspect linkages, adjust and lubricate as needed.
VENT DOORS
–Inspect linkages and bearings, adjust and lubricate as needed.
PAINTING
–Periodically clean and, if necessary, recoat all metal parts subject to corrosion.
Water Quality and Blowdown
BLOWDOWN
–Blowdown, or bleed-off, is the continuous removal of a portion of the
water from the circulating system. Blowdown is used to prevent the dissolved solids
from concentrating to the point where they will form scale. The amount of blowdown
required depends upon the cooling range (the difference between the hot and cold
water temperatures), the composition of the make-up water (water added to the sys-
tem to compensate for losses by blowdown, evaporation and drift). and the amount
of condensed water returned from the ClearSky heat exchanger modules. The follow-
ing table shows an approximate amount of blowdown required to maintain different
concentrations with various cooling ranges—these numbers are reduced by the % of
condensed water at a given weather condition:
BLOWDOWN–% OF CIRCULATING RATE
EXAMPLE:
7000 gpm circulating rate, 15° cooling range. To maintain 4 concentra-
tions, the required blowdown is .38% or .0038 times 7000 gpm which is 26.6 gpm.
Cooling Range
Number of Concentrations
X
5
.
1
X
0
.
2
X
5
.
2
X
0
.
3
X
0
.
4
X
0
.
5
X
0
.
6
.78
3°C
6°C
9°C
12°C
14°C
1.58
2.38
3.18
3.98
3
.
5
2
.
8
1
.
1
1
.
8
0
.
6
0
.
7
.
1
5
.
8
3
.
5
2
.
8
1
.
4
1
.
1
.
1
8
7
.
8
5
.
8
3
.
8
2
.
2
2
.
5
.
1
5
0
.
1
8
7
.
1
5
.
8
3
.
0
3
.
9
.
1
2
3
.
1
8
9
.
4
6
.
8
4
.
8
3
.
Multipliers are based on drift of 0.02% of the circulating water rate
➠
maintenance
