Westric DW Series, Installation, Operation And Maintenance Manual

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76-1002-00 Page 7 of 48
Thermostatic Expansion Valve.
This valve is located in the liquid line upstream the evaporator. It regulates the
amount of coolant injected into the evaporator, regardless of its the load condition. The type used in Westric
Precision equipment includes an overheat bulb sensor and external equalizer.

Viewing Glass
This is a transparent tube through which one can control the gas load and observe the
presence of moisture in the circuit.
Control Panel
The units are controlled by a built-in panel. The panel houses the controller, which is connected to other units via
interconnection terminals.
Therefore, the operation of the unit is entirely automatic.
The controller has a Flash memory which records the operating program and it also has multiple inputs and
outputs. The unit receives data from sensors and controls different elements of the system.
Using the display and keypad built into the controller makes it possible not only to obtain data about the conditions
in the room, but also the fault data log. Using an access code or password the user can enter the menu to change
temperature or humidity set points, cycling parameters, etc.
The control panel is able to receive the signal from a potential-free contact from a fire control room; this signal is
used to switch off the units in case the fire alarm is triggered.
Main elements of unit panel:

Modular terminals for power supply and alarm outputs

Contactors for each load with 24V coil

Microprocessed controller

Smoke detector
(Optional)

Power factor correction capacitors (Cos Phi)

General thermo-magnetic circuit breaker

Over current relay for motor and compressor contactors

Abnormal power supply sensor

Relative Humidity Sensor

Temperature Sensor

Auto-Manual
System

Terminals.
Terminals allow connecting the panel to the elements of the unit and to the power supply input.

Contactors.
Each element of the system is controlled by the Controller through a contactor with a 24V coil.

Controller.
Each system is controlled by a dedicated controller for air conditioners. The controller received
information about room conditions and possible malfunctions.

Smoke Detector (Optional)
This device detects the presence of smoke in the room.

Power Factor.
The power factor (cos phi) of the system load is corrected by means of power capacitors in
order to keep it within the values requested by power supply companies.

General thermo-magnetic circuit breaker.
All units have a general thermo-magnetic circuit breaker in their
internal board to protect it and also to allow for personnel safety during maintenance and service operations.

Over current relays.
These relays detect over current conditions in blower and compressor motors.

Controller alarm outputs.
The system has alarm outputs which are triggered when one or more units are out
of service.

Abnormal power supply sensor.
This sensor is used to detect under- or overvoltage conditions, missing
phase or phase asymmetry.
Humidity sensor.
This sensor sends analog information to the Controller about changes in room humidity.

Temperature sensor.
This sensor sends information to the Controller about changes in room temperature.
This sensor is located away from the controller.

Manual system.
This system allows units to be operated in refrigeration mode in case controller suffers any
damage. Its operation is totally independent from the controller. Room temperature is controlled by a
mechanical thermostat set at 23°C.