Table 6. Pressure drops for primary loop components at
minimum flow (ft of water)
Frame 3 Frame 4
405 A and 600 A
900 A and
1200 A
Air-Cooled Heat Exchanger 3 12
Water-Cooled Heat Exchanger 3 12
Drive 23 23
3/4-in. Tube (each foot) 0.17 0.68
1-in. Tube (each foot) 0.043 0.17
3/4-in. Straight Coupling 0.55 2.2
3/4-in. 45° Coupling 0.62 2.4
3/4-in. 90° Coupling 0.62 2.4
3/4-in. 90° Elbow Adapter 0.32 1.3
3/4-in. 45° Elbow Adapter 0.17 0.68
1-in. Straight Coupling 0.16 0.62
1-in. 45° Coupling 0.18 0.71
1-in. 90° Coupling 0.18 0.71
1-in. 90° Elbow Adapter 0.11 0.43
1-in. 45° Elbow Adapter 0.058 0.23
Plumbing
AFDK-SVU01C-EN 27
The flow in the secondary loop is established by the
pressure drop across the chiller evaporator. To calculate
the maximum piping distance for the secondary loop,
complete the following steps:
1. Measure the available pressure between the inlet and
the o
utlet of the chiller eva
porator. This value will vary
from chiller to chiller due to equipment and system
differences.
2. Use Table 7 to locate the pressure
drop
at minimum
flow due to the heat exchanger and fittings used.
Subtract these values from the available pressure and
save this result.
3. Use Table 7 to locate the pressure
drop
at minimum
flow due to each foot of tubing that is planned to be
used in the secondary loop. Divide the value obtained
in Step 2 by this number. The result of this calculation
is the maximum le
ngth of tubing that may be used in
the secondary loop.
Note: T
he maximum length of tube includes both the
suppl
y tube and return tube. The distance
between the chiller and heat exchanger should
be half the maximum tube length or less.
4. Verify that the tube length needed for installation does
no
t exceed
the maximum tube length obtained by this
calculation.
Note: I
f the calculated distance using 3/4-in. tubing
does not provide an a
dequate distance for
installation, recalculate the maximum distance
using 1-in. tubing and fittings.
Table 7. Pressure drops for secondary loop components
at mi
nimum flow (ft of water)
Frame 3 Frame 4
405 A 600 A 900 A 1200 A
Water-Cooled Heat
Exchanger
1 1.8 3 6.5
3/4 in. Tube (each foot) 0.066 0.14 0.23 0.47
1 in. Tube (each foot) 0.017 0.035 0.058 0.12
3/4 in. Straight Coupling 0.21 0.44 0.73 1.5
3/4 in. 45° Coupling 0.24 0.49 0.82 1.7
3/4 in. 90° Coupling 0.24 0.49 0.82 1.7
3/4 in. 90° Elbow Adapter 0.12 0.26 0.43 0.89
3/4 in. 45° Elbow Adapter 0.066 0.14 0.23 0.47
1 in. Straight Coupling 0.061 0.13 0.21 0.44
1 in. 45° Coupling 0.069 0.14 0.24 0.5
1 in. 90° Coupling 0.069 0.14 0.24 0.5
1 in. 90° Elbow Adapter 0.042 0.086 0.14 0.3
1 in. 45° Elbow Adapter 0.022 0.046 0.077 0.16
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