Lennox MRC 180, Application Manual

Application Guide 

•

 MWC-0410-E

• 3 •

FEATURES AND BENEFITS

ELECTRICAL BOX

The MWC is designed for 400V/3/50Hz supply.

-  Unit electrical cabinet, components and wiring in compliance 

with EN 60204-1 electrical directive.

-  400V/3/50Hz power supply (without neutral) with a single 

point of power connection.

-  IP24 protection class.
-  Recognized brand electrical components for ease of main-

tenance.

-  Main on/off switch mounted on the front panel.
-  DC50 user interface mounted on the front panel.
-  400/24 V transformer to supply the control circuit.
-  Labelled electrical wires to facilitate maintenance and dia-

gnostic.

-  Optional power and control circuit for the pumps.

CONTROL

CLIMATIC™ microprocessor based control is providing the 
following functions:

-  4 scheduling time zones per day over 7 days to allow energy 

consumption management according to the building use and 
environmental constraints.

- PI control of the water temperature with operating time 

equalisation of the compressors.

-  Intelligent advanced control algorithm to protect the compres-

sors against excessive short-cycling and to allow operation 
of the unit without buffer tank in most comfort air conditioning 
applications (e.g. unit with fan-coils). Refer to minimum ins-
tallation water loop volume recommendations.

-  Water pump control with operating time equalization and 

automatic change-over in case of a pump fault (Twin pump 
only).

-  Master/slave or cascade control of two chillers operating 

in parallel with operating time equalization and automatic 
change-over in case of a unit fault.

CLIMATIC™ is pre-factory con

fi

 gured with default settings 

allowing a fast commissioning on site. The DC50™ user interface 
with graphical display is easy to use, intuitive. Main customer 
parameters can be read or modi

fi

 ed without main power shut-off 

(Entering/leaving water temperatures, alarms, water set-points, 
high and low pressure readings).
The DS50™ service display (optional) is a .plug and play" 
controller that allows service people to read and modify all 
unit parameters (Unit settings, operating time and number of 
compressor starts, low and high pressure reading, read the 
history of last 32 faults...).

COMMUNICATION

The control board is equipped with a RS485 serial communication 
port to allow remote management through communication 
bus. 
According to the wished communication protocol, our control 
board can be 

fi

 tted with ModBUS®, LonWorks® or BacNET® 

communication interface (options).
The main control board has free dry contacts that allow remote 
control of the unit by wired cable:

-  Remote on/off of the unit.
-  Remote alarm reset to re-start the unit.
-  Alarm or alert indications.
- Free customer contact.

With the optional extension board BE50, it is possible to get 
additional customized digital or analog inputs/outputs for remote 
control of the unit:

-  Fault pumps (dry contact).
- Operation indication at 100% on circuit 1 or 2 (dry 

contact).

-  Dual water set-point management (dry contact).
-  Force heating or cooling mode (24V AC input).
-  Power limitation by disabling circuit 1 or 2 (24V AC input).
-  Force unoccupied mode (24V AC input).
-  Water set-point offset based on a 4-20mA signal. 

DIRECTIVES

The unit is built to meet European norms and standards & 
Eurovent certiFIcation performance standards.

.  DI 97/23/CE Pressure Equipment Directive.
.  DI 98/37/CE Machinery Directive.
.  DI 73/23/CE Low Voltage Directive.
.  DI 89/336/CE Electro Magnetic Compatibility Directive
.  EN 378-2 Safety and Environmental Directive.
.  The European Restriction of the Use of Certain Hazardous-

Substances (RoHS).