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EWWQ090G ÷ EWWQ720L - R410a - Water-cooled scroll chillers
EWLQ090G ÷ EWLQ720L - R410a - Condenser less
EWHQ100G ÷ EWHQ400G - R410a - Heat pump scroll chillers
Water cooled scroll chillers & heat pump
Operation
Manual
Operation Manual
8
EWWQ - EWLQ - EWHQ
Water colled scroll chiller &heat pump
D-EOMWC01203-15EN
If the pressure becomes too high in the refrigerant circuit, the relief valve will open to limit the
maximum pressure. If this happens switch off immediately the machine and contact your local
service organization.
1.4 Available sensors
1.4.1 Pressure transducers
Two electronic sensors are used to measure the evaporating and condensing pressure of each
circuit. The range of each sensor is clearly indicated on the sensor casing.
1.4.2 Temperature sensors
The evaporator and condenser water sensors are installed in the entering and leaving side.
Additionally each circuit installs a suction temperature sensor to monitor and control the
superheated refrigerant temperatures.
1.4.3 Thermistors
Each compressor is equipped with PTC thermistors which are immersed into motor windings for
motor protection. Thermistors trip to a high value in case the motor temperature reaches a
hazardous temperature.
1.5 Available Controls
1.5.1 Evaporator - Condenser pumps
The controller can regulate one or two evaporator pumps and takes care of automatic change-over
between pumps. It’s also possible to prioritize the pumps and temporarily disable one of the twos.
The controller can also regulate an unique condenser water pump.
1.5.2 Compressors
The controller can regulate two or four compressors installed on one or two independent refrigerant
circuit. All the safeties of each compressor will be managed by the controller
.
1.5.3 Expansion Valve
The controller can regulate an electronic expansion valve per each refrigerant circuit to guarantee
the best operation for the refrigerant circuit.
1.6 Customer Terminal Block Connections
1.6.1 General description
The contacts below are a
vailable at the user’s terminal block referred as MC24 or MC230 in the
wiring diagram. The following table summarises the connections at the user’s terminal block.
Description
Terminals Notes
Evaporator Flow Switch (mandatory) 724, 708
For potential-free contacts
Sampling voltage / current DC 24 V / 8 mA
Condenser Flow Switch (mandatory) 794, 793
For potential-free contacts
Sampling voltage / current DC 24 V / 8 mA
Cooling/Heating Remote switch
743,744
For potential-free contacts
Sampling voltage / current DC 24 V / 8 mA
Double setpoint
713,709
For potential-free contacts