51
RTAA-IOM-3
Table 4
Liquid Line Size for Horizontal and/or Downflow Lines
Circuit Size:
Liquid Line Size (OD”)
Total Equiv. Length (Ft)
100 Ton
85 Ton
70 Ton
25'
1 1/8
1 1/8
1 1/8
50'
1 3/8
1 1/8
1 1/8
75'
1 3/8
1 3/8
1 3/8
100'
1 3/8
1 3/8
1 3/8
125'
1 3/8
1 3/8
1 3/8
150'
1 5/8
1 3/8
1 3/8
175'
1 5/8
1 5/8
1 5/8
200'
1 5/8
1 5/8
1 5/8
225'
1 5/8
1 5/8
1 5/8
250'
1 5/8
1 5/8
1 5/8
275'
1 5/8
1 5/8
1 5/8
300':
1 5/8
1 5/8
1 5/8
Table 5
Equivalent Lengths of Non-Ferrous valves and Fittings
Line Size
Globe
Angle
Short
Long
Inches OD
Valve
Valve
Radius ELL
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
8.0
5.1
3 5/8
216
66
10.0
6.3
4 1/8
248
76
12.0
7.3
Reproduced by permission of Air conditioning and Refrigeration Institute.
Line Sizing
Equivalent Line Length
To determine the appropriate size for
field installed liquid and suction lines, it
is first necessary to establish the
equivalent length of pipe for each line.
An initial approximation can be made
by assuming that the equivalent length
of pipe is 1.5 times the actual length of
pipe. These assumed lengths can then
be used with the appropriate tables in
the Liquid Line Sizing section and the
Suction Line Sizing sections which
follow.
It is also necessary to know the
capacity (tons) of each circuit. Circuit
capacities for each RTAA unit are listed
in Table 3.
The following are examples of how to
determine line sizes.
Liquid Line Sizing
This example uses the unit installation
shown in Figure 31 and assumes an 85
ton circuit. The actual length of field
installed piping is 117 feet (80 + 8 + 8 +
21). Using the factor of 1.5, the
equivalent line length is 175 feet.
From Table 4, for horizontal and/or
downflow liquid lines, and assuming
an 85 ton circuit, 175 feet of equivalent
line requires a liquid line with an OD of
1 5/8 in.
There are 6 long-radius elbows in this
example. Using Table 5 and the pipe
OD of 1 5/8 in., these fittings represent
15.6 feet (6 elbows @ 2.6 feet each).
Therefore our new equivalent line
length is 132.6 feet (117 +15.6).
Referring back to Table 4, an 85 ton
circuit with 132.6 feet of equivalent pipe
length (use the dimension closest to
the calculated dimension) can use a
pipe O.D. of 1% in. rather than 1 5/8 in.
From Table 5 we see that the 6 elbows
of 1 3/8 in. have an equivalent pipe
length of 13.2 feet (6 elbows @ 2.2 feet
each). This further reduces the
equivalent pipe length to 130.2 feet
(117 + 13.2), and, as shown in Table 4,
still allows the use of 1 3/8 in. O.D. pipe.
Table 3
RTAA Circuit Capacities
Model
Circuit 1
Circuit 2
130
70
70
140
70
70
155
85
70
170
100
70
185
100
85
200
100
100
Summary of Contents for RTAA-130
Page 2: ... American Standard Inc 1991 ...
Page 8: ...8 RTAA IOM 3 ...
Page 24: ...24 RTAA IOM 3 ...
Page 50: ...50 RTAA IOM 3 Figure 30 Refrigerant Circuit Identification ...
Page 52: ...52 RTAA IOM 3 Figure 31 Remote Evaporator Piping Example ...
Page 59: ...59 RTAA IOM 3 Continued from Previous Page See Notes on Next Page ...
Page 63: ...63 RTAA IOM 3 Continued from Previous Page See Notes on Page 61 ...
Page 65: ...65 RTAA IOM 3 Continued from Previous Page See Notes on Page 61 ...
Page 76: ...76 RTAA IOM 3 ...
Page 92: ...92 RTAA IOM 3 Figure 51 Operator Interface Controls ...
Page 120: ...120 RTAA IOM 3 ...
Page 127: ...127 RTAA IOM 3 Continued from Previous Page 2307 1566C ...
Page 128: ...128 RTAA IOM 3 Figure 57 Unit Sequence of Operation RTAA 130 to 200 Tons 2306 9122A ...
Page 132: ...132 RTAA IOM 3 Figure 58 Operator s Log ...
Page 138: ...138 RTAA IOM 3 ...
