Figure 4: liquid line sizing – Sterlco GC Series Central Chiller User Manual
Page 20
GC Series Central Chillers
Chapter 3: Installation
20 of 79
Sizing Refrigerant Lines. To determine field installed liquid and discharge line sizes, first
establish the equivalent length of pipe for each line, valve, and elbow. Chiller capacity and
leaving water temperature range is also required. See Figure 3 on page 20 for lengths of
refrigerant valves and fittings.
Liquid Line Sizing. The liquid line should be sized as small as possible while maintaining
acceptable pressure drop to minimize the refrigerant charge. Liquid line risers must not
exceed 15 feet from the base of the air-cooled condenser. Horizontal runs do not require a
pitch. Insulation is not required unless the line is installed in a high ambient area, i.e., boiler
room or on a roof. Install a liquid line-charging valve to facilitate refrigerant charging. See
Figure 4 on page 20 for sizing information. See Figure 6 on page 23 for charge determination.
Discharge Line Sizing. Discharge line sizing is based on the velocity required for sufficient
oil return back to the compressor. See Figure 3: Pressure drop Equivalent Length in Feet for
Valves and Fittingson page 21 for discharge line sizing.
Note:
For horizontal runs, the discharge line should be pitched downward, in the
direction of flow, at a rate of 1/2” for every 10 feet. This will allow oil to flow
towards the condenser.
Figure 3: Pressure drop Equivalent Length in Feet for Valves and Fittings
Line Size
OD (inches)
Angle
Valve
Short
Radius EL
Long
Radius EL
7/8
28
7.8
5.3
1-1/8
29
2.7
1.9
1-3/8
33
3.2
2.2
1-5/8
34
3.8
2.6
2-1/8
39
5.2
3.4
2-5/8
44
6.5
4.2
Figure 4: Liquid Line Sizing
GCRC-70
GCRC-90
Total Equiv.
Length (Ft)
Liquid Line Size (OD")
Total Equiv.
Length (Ft)
Liquid Line Size (OD")
Horizontal
or
Downflow
Upflow
1-5 Ft
Upflow
6-10 Ft
Upflow
11-15 Ft
Horizontal
or
Downflow
Upflow
1-5 Ft
Upflow
6-10 Ft
Upflow
11-15 Ft
25
7/8
7/8
7/8
7/8
25
1-1/8
1-1/8
1-1/8
1-1/8
50
7/8
7/8
7/8
7/8
50
1-1/8
1-1/8
1-1/8
1-1/8
75
7/8
7/8
7/8
7/8
75
1-1/8
1-1/8
1-1/8
1-1/8
100
7/8
7/8
7/8
7/8
100
1-1/8
1-1/8
1-1/8
1-1/8
125
7/8
7/8
7/8
7/8
125
1-1/8
1-1/8
1-1/8
1-1/8
150
7/8
7/8
7/8
1-1/8
150
1-1/8
1-1/8
1-1/8
1-1/8
175
7/8
7/8
7/8
1-1/8
175
1-1/8
1-1/8
1-1/8
1-1/8
200
7/8
7/8
1-1/8
1-1/8
200
1-1/8
1-1/8
1-1/8
1-1/8
225
7/8
7/8
1-1/8
1-1/8
225
1-1/8
1-1/8
1-1/8
1-1/8
250
7/8
7/8
1-1/8
1-1/8
250
1-1/8
1-1/8
1-1/8
1-1/8
275
7/8
1-1/8
1-1/8
1-1/8
275
1-1/8
1-1/8
1-1/8
1-1/8
300
7/8
1-1/8
1-1/8
1-1/8
300
1-1/8
1-1/8
1-1/8
1-1/8
GCRC-105
GCRC-140
Total Equiv.
Liquid Line Size (OD")
Total Equiv.
Liquid Line Size (OD")