Trane RTAC 140-500 ton units (60 Hz) User Manual

54

RTAC-SVX01F-EN

 

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 equivalent length.

3.

Refer to 

 to determine the outside diameter that corresponds to the 

equivalent length computed in step # 2 for the height and leaving water tempera-
ture of interest.

Note: I

f the condenser is at the same elevation or above the evap

, use the 0 ft. 

column.

4.

With the outside diameter found in step # 3, use 

 to determine the equiv-

alent lengths of each fitting in the field installed piping.

5.

Sum the equivalent lengths of all the field installed elbows and valves.

6.

Add the length found in step # 5 to the actual length from step # 1. This is your 
new equivalent line length.

7.

Using 

 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 

 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 # 8 to the actual length from step # 1. This is the new 
equivalent line length.

10. With the equivalent line length found in step # 9, use 

 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.

 

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