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Air and Water cooled inverter chillers and heat pump
EWAD TZ - EWAD TZ B - EWWD VZ
Air and Water cooled inverter chillers
and heat pump
D-EOMZC00105-17EN
Operation Manual
11/84
1.6.1
Evaporator Flow Switch
Although the flow switch is offered as an optional, it is mandatory to install one and connect it to the digital
input terminals in order to enable chiller operation only when a minimum flow is sensed.
Operating the unit by-passing the flow switch input or without an appropriate flow switch may damage the
evaporator due to freezing. Operation of the flow switch must be checked prior to start up the unit.
1.6.2
Condenser Flow Switch (W/C units only)
Condenser flow switch is offered as an option but it’s not mandatory to connect it to the digital input terminals.
This input can be eventually closed by a jumper even if for a more reliable use it’s suggested to mount it. If not
installed, other protection will activate in order to protect the unit.
1.6.3
Double setpoint
This contact can be used to switch between two different LWT setpoints and, depending on the application,
between different modes of operation.
Ice operation must be selected in case of ice storage application. In this case the UC will run the chiller in
on/off mode, switching all the chiller off as soon as the setpoint is reached. In this case the unit will run to full
capacity and then will switch off applying an ice delay different chiller starts.
1.6.4
Current limit (optional)
This optional feature enables a capacity control of the unit in order to limit the input current. The current limit
feature is included in the Energy Meter option. The limiting signal will be compared with a limiting value set on
the HMI. By default the current limit setpoint is selected through the HMI; an external 4-20 mA signal can be
enabled to allow a remotely changeable setpoint.
1.6.5
External Fault
This contact is available to report to the UC a fault or a warning from an external device. It could be an alarm
coming from an external pump to inform the UC of the fault. This input can be configured as a fault (unit stop)
or a warning (displayed on the HMI without any action on the chiller).
1.6.6
Rapid Restart (optional)
Purpose of the rapid restart feature is to let the unit restart in the shortest possible time after a power failure,
and then recover in the shortest possible time (maintaining the reliability level of the normal operations) the
capacity it had before the power failure. The rapid restart is enabled by the enable switch.
1.6.7
Remote On-Off
This unit can be start
ed through a remote enable contact. The Q0 switch must be selected to “Remote”.
1.6.8
General Alarm
In case of a unit alarm, this output is closed thus indicating a fault condition to an externally connected BMS.
1.6.9
Compressor Status
The digital output is closed when the related circuit is in run state.
1.6.10 Circuit Alarm (optional)
This option is included with the “Rapid Restart” option. The related digital contact is closed in case of alarm on
a circuit.