Liebert 104 165 User Manual

The Liebert condenser is low-profile direct-drive propeller fan-type air cooled unit suitable for mount-

ing outdoors. It provides for the heat rejection of either one or two separate refrigeration circuits, 

matching heat rejection capacity varying with the outdoor ambient temperatures with each corre-

sponding compressors heat rejection requirements. Constructed with an aluminum cabinet and a cop-

per-tube aluminum fin coil, the unit is quiet and corrosion resistant. The condenser is quickly and 

easily installed, because all internal wiring is completed at the factory with only electrical connec-

tions to be made at the job site. All electrical connections and controls are enclosed in an integral 

weatherproof section of the condenser.

Fan speed control utilizes a wave-chopper control to vary the air volume over the condenser coil, 

based on refrigerant head pressure. The fan motor next to the electrical panel (two fans on 6-fan and 

8-fan models) is a single-phase, permanent split capacitor motor with motor speed adjusted in 

response to refrigerant pressure. The balance of fans on multi-fan units cycle on ambient thermostats. 

The control system provides refrigerant head pressure control for outdoor ambients as low as 

-20°F (-28.9 °C).

VFD Condenser control system utilizes a variable frequency drive, inverter duty fan motor operating 

from 0% to 100% motor RPM based on head pressure, sensed by refrigerant pressure transducers. 

VFD, ambient-temperature thermostat(s), motor overload protection and electrical control circuit are 

factory-wired in the integral control panel. VFD controls the fan adjacent to the connection end of the 

condenser and remains energized with active compressor operation. The balance of fans on multi-fan 

units cycle on ambient thermostats. This system provides refrigerant head pressure control for out-

door ambients as low as -20°F (-28.9°C).