Blue Box SIGMA 2002 - Technical Characteristics; Compressors; Refrigerant Circuit; Electrical Panel

Blue Box - 1
SIGMA 2002 - water chiller
Water-cooled liquid chillers with hermetic scroll compressors and plate type evaporator, suitable for inside
installations.
TECHNICAL CHARACTERISTICS
UNIT FRAME
Self supporting frame, constructed in galvanized sheet steel with RAL 7032 powder paint baked at 180°C to
provide a durable weatherproof finish.
Models 3.2 to 7.2 and model 14.4 are completely enclosed by painted steel panels fully lined with a sound
absorbing material.
On models 8.2 to 13.2 only the upper compartment, which contains the compressors, is fully enclosed on all sides
by painted steel panels fully lined with a sound absorbing material.
On models 8.2 to 13.2 only the upper compartment , which contains the compressors, and the separator between
this compartment and the lower part of the unit are enclosed by painted steel panels fully lined with a sound
absorbing material.
Models 16.4 to 26.4 do not have panels.
COMPRESSORS
Hermetic scroll type with orbital motion, connected in tandem and equipped with oil level sight glass, Klixon
internal thermal protection and oil equalisation line.
EVAPORATOR AND CONDENSER
Brazed plate type in 316 AISI stainless steel. Thermal insulation of evaporator is provided by closed cell expanded
material. Each evaporator is equipped with a low water temperature probe for freeze protection and each unit is
equipped as standard with a mechanical flow switch.
REFRIGERANT CIRCUIT
Comprising: liquid valve, charge connection, liquid sight-glass, filter/dryer, thermostatic expansion valve with
external pressure equalisation, high and low pressure switches for 2-compressor models.
For 4-compressor models high and low pressure values and relative condensation and evaporation temperatures
are measured by pressure transducers that relay the signals to the controller so that they can be read directly on
the display. The high pressure side of the circuit is equipped with high pressure switches and relief valves.
ELECTRICAL PANEL
The electrical panel includes:
- main switch
- fuses for the auxiliary and power circuit
- compressor contactors
- microprocessor mCHILLER for 2 compressor units and PCO
2
for 4 compressors units, controlling the following
functions:
- water temperature regulation
- freeze protection
- compressor time intervals
- compressor start sequence and automatic lead/lag selection
- alarm reset
- common alarm contact for remote signalling
- operating and alarm indicator LEDs
- LCD display of the following information:
- water inlet and outlet temperature
- programmed temperature set-point and differential
- alarms description
- compressor hours run meter for units with PCO
2
control
- number of starts of the unit and the compressors
- high and low pressure values and relative condensation and evaporation temperature values.
Electrical power supply [V/f/Hz]: 400/3~/50 ±5%