Blue Box - 2
SIGMA UNIT VERSIONS
SIGMA 2002/HP: reverse cycle heat pump
The heat pump version operates as a water cooled chiller in summer and a water to water heat pump in winter
by reversing the refrigerant flow to suit the required operating mode.
In addition to the components of version SIGMA 2002, the heat pump version includes:
REFRIGERANT CIRCUIT: 4-way reversing valve and a second thermostatic expansion valve.
ELECTRICALPANEL:Microprocessor programmed for summer/winter changeover(the Macroplusmicroprocessor
is used on 4 compressor HP units).
SIGMA 2002/LE: motocondensing unit
The unit is designed to operate with a remotely located refrigerant to air evaporator. It is supplied without a
refrigerant to water evaporator and thermostatic expansion valve. The solenoid valve on the liquid line issupplied
asstandard. Models 3.2 to13.2 have mchiller controland theremainderofthe rangeis supplied withoutcontrol.
The standard supply is ON/OFF for each compressor from a digital entry.
SIGMA 2002/LE/HP: motocondensing unit
The unit is designed to operate with a remotely located refrigerant to air evaporator. It is supplied without a
refrigerant to water evaporator and thermostatic expansion valve.
The solenoid valve on the liquid line and liquid receivers are supplied as standard. Models 3.2 to 13.2 have
mCHILLER control and the remainder of the rangeissuppliedwithoutcontrol. The standard supply is ON/OFF for
each compressor from a digital entry.
SIGMA 2002/LC: motoevaporating unit.
The unit is supplied without a water cooled condenser and is designed to be connected to a remotely located air
cooled condenser.
SIGMA 2002 / LC /HP: motoevaporating unit
The unit is supplied without a water cooled condenser and is designed to be connected to a remotely located air
cooled condenser.
The solenoid valve on the liquid line and the liquid receivers are supplied as standard.
ACCESSORY VERSIONS
SIGMA 2002 /DC: unit with heat recovery condenser.
Not available for HP versions.
Inaddition to thecomponents of version SIGMA 2002 this unit includesa 100% heatrecovery condenser, for the
production of hot water, and a liquid receiver on each refrigerant circuit.
SIGMA 2002 /DS: unit with desuperheaters
Available for all models. Abrazed plate type heat recovery exchanger (desuperheater) is arranged in series with
the condenser. Also available on all HP models. In this case an isolating valve must be fitted on the water
recovery circuit and be closed during heat pump mode operation as described in the manual.
CONTROLS AND SAFETY DEVICES
- High pressure switch with manual reset.
- High pressure safety, with manual reset, controlled by the unit controller on four compressors models.
-Low pressure safety switch, with manual reset, controlled by the unitcontroller for four compressor models, low
pressure switch, with manual reset, controlled by the unit microprocessor for the two compressors models.
- High pressure relief valve
- Chilled water temperature sensor (at the evaporator inlet); on four compressors model it is installed on one
evaporator only.
- Freeze protection sensor at the outlet of each evaporator.
- Mechanical flow switch supplied as standard as kit with the unit.
-Compressorover-temperatureprotection
TESTING
The units are subjected to a dry run in the factory and supplied complete with oil and refrigerant.
