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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
EWWQ - EWLQ - EWHQ
Water cooled scroll chiller &heat
pump
D-EOMWC01203-15EN
Operation Manual
11
2 GENERAL DESCRIPTION
2.1 General
The UC is a system for controlling single or dual-circuit water-cooled liquid chillers / heat-pump.
The UC controls compressor start-up necessary to maintain the desired heat exchanger leaving
water temperature.
The unit controller can also controls a three way valve or a cooling tower to perform a condensing
control. One of the following three feedbacks can be selected as condensing target:
-
Condenser leaving water temperature
-
Condenser entering water temperature
-
Condensing saturated refrigerant temperature
Safety devices are constantly monitored by the UC to ensure their safe operation. UC also gives
access to a Test routine covering all inputs and outputs. The controller can work in accordance
with three independent modes:
Local mode: the machine is controlled by commands from the user interface.
Remote mode: the machine is controlled by remote contacts (volt-free contacts).
Network mode: the machine is controlled by commands from a BAS system. In this case, a
data communication cable is used to connect the unit to the BAS.
When the UC operates autonomously (Local or Remote mode) it retains all of its own control
capabilities but does not offer any of the features of the Network mode.
2.2 Abbreviations used
In this manual, the refrigeration circuits are called circuit #1 and circuit #2.
The following abbreviations are used frequently:
UC
Unit controller
HMI
Human Machine Interface
A/C
Air Cooled
W/C
Water Cooled
CL
Condenser Less
CP
Condensing Pressure
EP
Evaporating Pressure
CSRT Condensing Saturated Refrigerant Temperature
ESRT
Evaporating Saturated Refrigerant Temperature
ST
Suction Temperature
SSH
Suction SuperHeat
EXV
Electronic Expansion Valve
ELWT Evaporator Leaving Water Temperature
EEWT Evaporator Entering Water Temperature
CLWT Condenser Leaving Water Temperature
CEWT Condenser Entering Water Temperature