Trane RTAA-100, Installation & Maintenance Manual

Page: 42 / 178

42 RTAA-SVX01A-EN
Installation — Remote Evaporator
Suction Accumulator Sizing
Installations similar to those in Figure 18 and 20 will require that the suction
accumulator be extended at least by the amount shown in 7 . The suction
accumulator length in feet is dependent upon: circuit tonnage, suction line
O.D., and actual liquid line length.
The following example uses Figure 23 and assumes a 50 ton circuit with a
2-5/8 inch O.D. suction line. Figure 23 illustrates an installation where the
remote evaporator is 11 feet above the outdoor condensing unit. A liquid line
at the same elevation as the evaporator runs horizontally 25 feet. Then it
drops 11 feet to the same elevation as the suction line connecting points on
the outdoor condensing unit, and runs horizontally 5 feet to the outdoor
condensing unit. From
Figure 23 , the actual length of liquid line is 41 feet (25
+ 11+5). With the previously mentioned assumptions, Table 7 indicates 15
feet of 2-5/8 inch O.D. suction accumulator needs to be added. Figure 24
shows one method of piping the additional 15 feet.
NOTE: In this example, if the liquid and suction lines had dropped the 11
feet from the evaporator and then run the 25 feet horizontal at the outdoor
condensing unit's elevation, the 15 feet of suction accumulator would not be
required.
NOTE: When sizing suction line diameters, the length of the suction
accumulator should be included in any computations.
The height of the suction accumulator, specified in Table 7 , may not exceed 4
inches above the suction line connecting point at the outdoor condensing
unit. In addition, the suction accumulator must be pitched toward the
compressor 1/2 inch per 10 feet of horizontal run.