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

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RTAC-SVX01F-EN

 

For this example, refer to 

. Assume a 70 ton circuit 

and a leaving water temperature of 49 degrees F.

1.

From 

, the actual length of field installed piping is:

80 + 8 + 8 + 21 = 117 feet

2.

Estimate equivalent line length: 

117 feet x 1.5 = 175 feet

3.

From 

 for a 70 ton circuit, for 175 equivalent feet the OD is 1.375 inches.

Note: use the 0 ft. column since the condenser is above the evap

4.

In 

 there are six long-radius elbows. From 

, for 1.375 inch 

elbows, the equivalent feet is:

6 elbows x 2.2 feet = 13.2 feet

5.

Adding equivalent feet from step #4 to step #1 gives: 

13.2 feet + 117 feet = 130.2 feet

6.

From 

, for a 70 ton circuit, for 125 equivalent feet (nearest to 130.2), the 

O.D. is 1- 3/8 inches.

Liquid Line size = 1-3/8 inches

The steps to compute suction line size are as follows:

1.

Break the suction line into it's Vertical/Upflow and Horizontal/Downflow compo-
nents. 

2.

From 

, select the appropriate Vertical/Upflow suction line outside diame-

ter according to the circuit tonnage. This is the diameter of the upflow suction line 
and any fittings in the upflow line.

3.

From 

, select the appropriate Horizontal/Downflow suction line outside 

diameter according to the circuit tonnage. This is the diameter of the upflow suc-
tion line and any fittings in the upflow line.

Example Suction Line Sizing
For this example, refer to 

 assume a 70 ton circuit and a leaving 

water temperature of 49 degrees F.

1.

From 

, the vertical/upflow suction line is: 3 5/8” O.D.

2.

From 

, the horizontal/downflow line is: 3 5/8” O.D.

40 - 60

3 5/8”

3 5/8”

4 1/8”

4 1/8”