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Liebert
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Challenger 3000
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7.2.1 Line Voltage
Line voltage electrical service is required for all condensing units at the location of the condensing
unit. This power supply does not have to be the same voltage as the indoor unit. This separate power
source may be 208, 230, 460 or 575V, 60 Hz; or 200, 230, or 380/415V, 50 Hz. A disconnect switch is
required and must be mounted per local and national codes to isolate the unit for maintenance.
7.2.2 Low Voltage
The control cable between the condensing unit and the evaporator unit is connected between
terminals 1,2 and 3 on the terminal strip in the evaporator unit and the condensing unit control box.
A fourth wire is required on systems with hot gas bypass. NEC Class 1 wiring is required. Glycol-
cooled units also require a two-wire control connection to the drycooler and pump package.
7.3 Piping Considerations
7.3.1 Refrigerant Loop
NOTICE
Risk of improper refrigerant charge. Can cause equipment damage, environmental
degradation and violation of national, state and local law.
Follow all applicable codes for handling refrigerant.
R22 and R407C are similar in properties—proper safety equipment and proper refrigeration
tools are required on both types. Check unit nameplate for correct refrigerant type before
topping off or recharging a system.
R407C refrigerant must be introduced and charged from the cylinder only as a liquid.
NOTICE
Risk of improper piping installation. Can cause contamination of hygroscopic oil with water.
When installing field piping, care must be taken to protect all refrigerant lines from the
atmosphere, especially when using refrigerants, such as R407C which requires use of polyol
ester oils. Do not allow the piping to stand open to air for more than 15 minutes. Units
designed for R407C have a compressor that contains polyol ester oil, which is very
hygroscopic; that is, it quickly absorbs water from the air. The longer the compressor piping is
left open to air, the harder it will be to fully evacuate. If left open too long, the polyol ester oil
may need to be replaced before achieving the required vacuum level.
!
WARNING
Risk of explosive discharge from high-pressure refrigerant. Can cause injury or death.
This unit contains fluids and gases under high pressure. Relieve pressure before working with
piping.
NOTE
Complete all piping and evacuate lines before connecting quick connects when using an
optional sweat adapter kit and field installed hard piping.
Follow all proper brazing practices including a dry nitrogen purge to maintain system
cleanliness.