Emerson Liebert MC Microchannel Outdoor Condenser 28 - 220kW 用户手册
Introduction
5
Liebert
®
MC
™
1.1.2 Liebert Lee-Temp
™
Refrigerant Control
The Liebert Lee-Temp head pressure control system utilizes head pressure control valve(s), extra
refrigerant and insulated refrigerant receiver(s) with heater pads to assist system starting and to
maintain proper operating head pressures in outdoor ambient temperatures below the rating point of
the Liebert MC control type. The system works by flooding the condenser coil with liquid refrigerant
to a level that balances the system condensing requirements with the condenser coil surface available
to reject the system heat. During the summer, the system requires the entire condenser coil surface
for heat rejection and most of the refrigerant is stored in the receiver. In the winter, the same amount
of heat can be rejected by only a fraction of the coil surface. As head pressure begins to fall, the control
valve restricts the flow of liquid refrigerant existing from the condenser. This extra liquid refrigerant
reduces the effective condenser surface area available for heat transfer. The head pressure control
valve also bypasses hot gas into the receiver to warm the liquid and maintain liquid pressure for
proper operation of the expansion valve. Liebert Lee-Temp kit is optional for condensers and is
field-installed. Condenser control boards are factory-configured for Liebert Lee-Temp if ordered with
Liebert Lee-Temp receivers. They can be field-configured if Liebert Lee-Temp system is added later.
1.2
Sound Level
Liebert MC condensers utilize low air resistance coil(s) and slower speed fan motors to yield the
required heat rejection at significantly lower sound levels. EC fans are designed to yield the same
maximum sound levels at summer design conditions to help your facility meet noise codes with
moderate operating sound levels.
1.2.1 Liebert Quiet-Line Match Up
Special match ups of premium condensers are available for applications needing to meet even lower
governmental sound regulations. Lower sound levels are achieved by oversizing the condenser, which
will decrease the maximum airflow and sound level produced by the condenser at design outdoor air
temperatures. This feature requires special setup of the indoor unit. Liebert Lee-Temp may be
required for these applications.
1.3
Surge Protection Device (Optional)
An optional surge protection device (SPD) can be field-wired to protect the condenser from surges that
threaten sensitive equipment. The condenser’s electrical panel provides a terminal block to allow the
SPD to be wired in parallel with the high-voltage power. An additional low-voltage terminal block is
provided on condensers with Premium Control Boards to allow monitoring of the SPD alarm circuit.
The Liebert PowerSure CM
The Liebert PowerSure CM
™
surge protection device provides 50kA per mode of surge current
protection. An illuminated green LED indicates the SPD is On and providing full protection. An
illuminated red LED indicates that the device’s protection may have been reduced and may require
replacement.
Both lights extinguished indicates there is no power to the condenser or the condenser disconnect is in
Both lights extinguished indicates there is no power to the condenser or the condenser disconnect is in
the Off position.