Installation - Mechanical — Remote Evaporator Option
RTAC-SVX01J-EN 59
Line Sizing
To determine the appropriate outside diameter for field
installed liquid and suction lines, it is first necessary to
establish the equivalent length of pipe for each line. It is
also necessary to know the capacity (tons) of each circuit.
Circuit capacities for each RTAC unit are listed in Table 1,
p. 12 through Table 10, p. 21.
Liquid Line Sizing Steps
The steps to compute liquid line size are as follows:
1. Compute the actual length of field installed piping.
2. Multiply the length from step # 1 by 1.5 to estimate the
equi
valent length.
3. See Table 29, p. 58 to determine outside diameter
corresponding to equivalent length computed in step
2
for height and leaving water temperature of interest.
Note: If
condenser is at same elevation or above evap,
use 0 ft. column.
4. With the outside diameter found in step # 3, use
Table 30, p. 59 to determine the equivalent lengths of
each fitting in the field installed piping.
5. Add equivalent lengths of all field installed elbows and
valves.
6. Add the length found in step#5t
o the actual length
from step # 1.This is your new equivalent line length.
7. Using Table 29, p. 58 again, find the outside diameter
that corresponds to the new equivalent line length
from
step # 6. If it is the same as step #3, this is the final
equivalent length. Otherwise, proceed to the next step.
8. Using Table 30, p. 59 and the new outside diameter
found in step # 7, find the equivalent line length of each
valve
and fitting, and sum them.
9. Add the length found in step#8t
o the actual length
from step # 1.This is the new equivalent line length.
10. With the equivalent line length found in step # 9, use
Table 29, p. 58 to select the proper outside diameter for
the liquid lines. If the same as in step #7, this is your
final
equivalent line length. Otherwise, repeat step #7.
Note: L
ocation and quantity of suction accumulator is
dependent upon the unit configuration.
Table 30. Equivalent lengths of non-ferrous valves and
fittings (feet)
Line Size
Inches OD
Globe
Valve
Short Angle
Valve
Short Radius
ELL
Long
Radius
ELL
1-1/8 87 29 2.7 1.9
1-3/8 102 33 3.2 2.2
1-5/8 115 34 3.8 2.6
2-1/8 141 39 5.2 3.4
2-5/8 159 44 6.5 4.2
3-1/8 185 53 8 5.1
3-5/8 216 66 10 6.3
4-1/8 248 76 12 7.3
Table 31. Required length of field installed suction line accumulator (ft)
Actual Feet
of field
installed
liquid line
70 Ton Circuit
(a)
85 Ton Circuit 100 Ton Circuit 120 Ton Circuit
O.D. of Field Installed Liquid Line
1 3/8” 1 5/8” 2 1/8” 1 3/8” 1 5/8” 2 1/8” 1 5/8” 2 1/8” 2 5/8” 1 5/8” 2 1/8” 2 5/8”
Length of 3 5/8” Suction
Accumulator
Length of 3 5/8” Suction
Accumulator
Length of 4 1/8” Suction
Accumulator
Length of 4 1/8” Suction
Accumulator
10 43 44 45 52 52 53 43 44 46 52 53 54
20 45 46 49 53 54 57 45 47 50 53 55 58
30 46 48 52 54 56 60 46 49 53 55 58 62
40 48 50 55 56 58 63 48 52 57 56 60 66
50 49 52 59 57 60 67 49 55 61 58 63 70
60 51 54 62 59 62 70 51 57 65 59 66 74
70 52 56 65 60 64 73 53 60 69 61 68 78
80 53 58 69 62 66 77 54 62 73 62 71 81
90 55 60 72 63 68 80 56 65 77 64 73 85
100 56 62 75 64 70 83 57 68 81 66 76 89
110 58 64 79 66 72 87 59 70 85 67 79 93
120 59 66 82 67 74 90 60 73 89 69 81 97
130 61 68 85 69 76 93 62 75 93 70 84 101
140 62 70 89 70 78 97 63 78 97 72 86 105
150 64 72 92 72 80 100 65 81 101 73 89 109
160 65 74 95 73 82 103 67 83 105 75 92 113
170 66 76 99 75 84 107 68 86 108 76 94 117
180 68 78 102 76 86 110 70 88 112 78 97 121
190 69 79 105 77 88 113 71 91 116 80 99 125
200 71 81 109 79 90 117 73 94 120 81 102 129
(a)Circuit 2 of 155 ton premium unit requires ad additional 10 feet of suction accumulator length.
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