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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
49/84
display in the circuit status as “Run: High Discharge Temp
”. The status is automatically cleared when the
discharge temperature falls below the hold limit.
5.3 Condensation Control (A/C units only)
Condensing Pressure is controlled in order to achieve best chiller efficiency within compressor envelope limits.
Condenser pressure control is achieved through fan staging and/or fan speed control, when the unit is
equipped with fan speed regulation option. See chapter 4.3.3 for more details.
In particular, when the chiller operates at a low ambient temperature, a minimum condenser saturated
temperature is imposed, based on saturated evaporating temperature. This allows the compressor to operate
within its envelope. This setpoint is further increased (see figure below) by a quantity which depends from
outside ambient temperature and compressor load in achieve the best efficiency point, i.e. minimum energy
consumption of compressor and fans.
5.3.1
Fan Settings (A/C units only)
The unit may be equipped with on/off fans, inverter fans or brushless fans. Based on the fan type, different
settings are required to the chiller controller and/or to the inverters.
5.3.1.1 Fan VFD Settings
Units may be equipped optionally or as a standard with fan VFD control. Each circuit is organized with two
steps, arranged as per the following table. The two stages are activated according to the same logic as
described in the previous chapter.
* * * * * * * * *
Inverters used for fan control may be of two types, according to the number of fans which they control. Most
parameters are valid for all, some other parameters (9900 series) are specific for the inverter and fan type
used. For further details please refer to the instruction manual of the inverters included in the documentation
of the unit.
Inverter parameter list
– 1 fan control
Parameter
Description
Fan Type
AC900
AC700
1611
Param View
Long View
Long View
1002
Ext commands
NOT SEL
NOT SEL
1301
Min AI1
0%
0%
1601
Run Enable
DI1
DI1
1604
Fault Reset
DI1
DI1
2006
Undervoltage
Enable
Enable
2101
Start Function
AUTO
AUTO
2202
Acceleration Time
10 s
10 s
Evap. Sat. Temp.
Cond. Sat.
Temp.
Min Cond Press
Cond Press @ 30% load
Cond Press @ 50% Load