Emerson Liebert MC Microchannel Outdoor Condenser 28 - 220kW Manuel D’Utilisation

The Liebert MC Premium Efficiency Control takes approximately 30 seconds to boot up once power is 

applied to the condenser. The LED on the Premium Efficiency Control Board reads “888” while the 

board is booting up. Once the control has booted up, the display shows “F00” and then the value for 

F00. With the control operational, the condenser fan(s) turn in less than 5 seconds after receiving a 

signal from the indoor unit that the compressor(s) are On. Consider using UPS equipment on both 

data center cooling units and Liebert MC condensers to maintain uninterrupted cooling capability.
For the first 60 seconds of operation after the compressor turns on, the condenser fan(s) will run at a 

fixed speed, set at the factory, based on ambient temperature: faster at higher temperatures, slower 

at lower temperatures. After 60 seconds, the control adjusts the fan speed based on the liquid 

pressure transducer. If the liquid pressure transducer fails, the condenser uses temperature sensors 

to control the fan speed based on the liquid line temperature. The condenser fans continue to operate 

for approximately 30 seconds after compressors turn Off.
The Liebert MC fans have various alarm conditions, such as loss of voltage and loss of control signal, 

that will stop the condenser fans. Once the alarm condition is no longer present the Liebert MC fans 

will turn on automatically if compressors are On.

The Liebert MC Premium Efficiency Control board has a stacked board arrangement. There are three 

seven-segment LED’s and four keys as human machine interface (see Figure 24).

301471
Pg. 2, Rev. 3

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Spare Digital
Outputs (Not
Used)

Call for
Cooling

Remote
Shutdown

Fan
Contactor
Output

Mother
Board

24VAC

Earth
Ground

Fan 4

Fan 3

Fan 2

Fan 1

CPU
Board

RS485
Communication
to Fans

Spare Analog
Outputs (Not Used)

Communication
from
indoor unit

Communication
from
indoor unit

CANbus

Service

Pressure
Inputs

Circuit 1

Circuit 2

Circuit 1

Circuit 2

Ambient

Temperature
Inputs

Alarm & Shutdown
Circuits

Ethernet and CANbus addressing
and signal indication

Indicator Lights: ON - Signal Present

Indicator Lights:
ON - Signal
Present

Control Fuses

RS485 Service
Terminal

BAR CODE

24VAC

CAUTION
For Continued Protection Against Risk of Fire,
Replace Only With Same Type and Rating of Fuse

ACM01M1

VER:A02
2010.08.10

BAR CODE

Human
Machine
Interface
(HMI)

Circuit 1
Circuit 2

F3 T3.15A, 250VAC

F2 T3.15A, 250VAC

ACM01U1 VER:A03 2010.08.10

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Fuses are rated to 3A/250V

#1 

#3

#2

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