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Air-Cooled Models—Self-Contained Compressor
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3.4 Fan Speed Control Systems
The Variable Fan Speed Control systems (FSC & VFD) uses pressure-activated electronic fan speed
control systems and remotely located thermostat(s) to ensure operation at ambient temperatures as
low as 0°F (-18°C). For this ambient temperature range, the VFD Control Condenser must be used
with digital scroll indoor units and can be used for energy savings with any Liebert Challenger 3000
unit.
Variable Fan Speed Control Piping
A discharge line and a liquid line must be field-installed between the indoor unit and the outdoor con-
denser. See Figures 15 and 16 for details.
Table 6 Equivalent lengths (feet) for various pipe fittings
Copper Pipe
O.D. in.
90 Degree
Elbow Copper
90 Degree
Elbow Cast
45 Degree
Elbow Tee
Gate
Valve
Globe
Valve
Angle
Valve
1/2 0.8 1.3 0.4 2.5 0.26 7.0 4.0
5/8 0.9 1.4 0.5 2.5 0.28 9.5 5.0
3/4 1.0 1.5 0.6 2.5 0.3 12.0 6.5
7/8 1.45 1.8 0.8 3.6 0.36 17.2 9.5
1-1/8 1.85 2.2 1.0 4.6 0.48 22.5 12.0
1-3/8 2.4 2.9 1.3 6.4 0.65 32.0 16.0
1-5/8 2.9 3.5 1.6 7.2 0.72 36.0 19.5
Refrigerant trap = 4 times equivalent length of pipe per this table.
Table 7 Indoor unit refrigerant charge lb (kg)
Model
R407C
Approximate Charge
lb (kg)
42A/40A 0.9 (0.4)
67A/65A 1.4 (0.6)
Table 8 Line charges - refrigerant per 100 ft. (30 m) of Type “L” copper tube
O.D.
R407C
Liquid Line
lb (kg)
Hot Gas Line
lb (kg)
1/2" 7.3 (3.3) 1.3 (0.6)
5/8" 11.7 (5.3) 2.1 (1.0)
3/4" 16.6 (7.5) 3.0 (1.4)
7/8" 24.4 (11.1) 4.4 (2.0)
Table 9 Condenser refrigerant (per serial tag)
Model
R407C
Approximate Charge
lb (kg)
Fan Speed
Liebert
Lee-Temp*
083 8 (3) 25 (12)
104 9 (4) 37 (17)
165 15 (6.8) 50 (22.7)
* Charge includes the receiver charge.