Electrical Connections; Low-Voltage Control Wire Connections; Table 13 Design Refrigerant Pressures; Table 14 Application Limits - Liebert Prop Fan Condensing Unit User Manual

2.6

Electrical Connections

Each unit is shipped from the factory with all internal wiring completed. All power, control wiring
and ground connections must be made in accordance with the National Electrical Code and local
codes. Refer to equipment nameplate regarding wire size and circuit protection requirements. Refer to
Figures 5, 7 and 8 and electrical schematic (reference Figures 9 through 11) when making
connections. A manual electrical disconnect switch should be installed within 5 feet (1.6m) of the unit
in accordance with codes.
WARNING
!
Risk of electric shock. Can cause injury or death.
Disconnect all local and remote electric power supplies before working within. Use a
voltmeter to be sure power is turned off before making any electrical connections.
NOTICE
Risk of incorrect phase sequencing. Can cause equipment damage.
Three-phase power must be connected to the unit line voltage terminals in proper sequence so
that the scroll compressor rotates in the correct direction.
The three-phase scroll compressor requires proper phasing to ensure correct motor rotation. The
component connections have been phase synchronized at the factory. Power phasing should be
changed only at the line voltage supply to the unit. To change phasing, switch any two power leads to
the unit. Observe system pressures to determine whether the unit is operating properly.
NOTICE
Risk of compressor slugging. Can cause equipment damage.
Apply power to condenser 8 hours before operating the system. This time is required to allow
liquid refrigerant to be driven out of the compressor. This is especially important at low
ambient temperatures. The compressor crankcase heater is energized as long as power is
supplied to the unit.
Table 13 Design refrigerant pressures
Suction
Discharge
(At Design Ambient)
High-Pressure Cutout
Table 14 Application limits
Input voltage
Minimum
-10%
-5% 208/230V
single-phase
2.6.1

Low-Voltage Control Wire Connections

Field-supplied four-wire control connection (10-wire on 8-ton units) is required between the outdoor
condensing unit and the evaporator. Refer to Figures 5, 7 and 8 and to unit electrical schematic and
Figures 9 through 11.
53 - 95 PSIG
(365 to 655 kPa)
280 psig (1930 kPa)
400 psig (2760 kPa)
Dry Bulb Air Temperature at Condenser
Maximum Minimum
+10% -30°F (-34°C)
Maximum
115°F (46°C) Std
Ambient & Quiet-Line
125°F (52°C)
High Ambient Models
21
Installation