Installation and operation manual
24
EWWD440~850AAYNNO**
Packaged water-cooled water chillers
4PW25558-1B
Demand setting screen
How to determine the current demand setpoint
1.
Determine the upper operating current limit value you want=C.
2.
Calculate the upper operating current limit value per compressor D.
D=C/2.
3.
Calculate the current demand setpoint B. B=D/A1x100 where A1 is
the reference current per compressor as in
4.
Set the current demand percentage on the touch panel “SETTING
(1/2)” screen.
Units control thermo
This function is designed for preventing inefficient operation due to to
low partial load. One compressor will be stopped automatically in
case the load reduces to a certain level. (Units control thermo OFF)
At the moment that the cooling load increases again, the number of
compressors in operation returns to 2 units automatically again.
(Units control thermo ON)
Compressor starting order rotation function
For planning the load levelling of the 2 compressors, this unit has a
function to switch the starting order of compressors. In case the units
control thermo turns OFF, thus requiring one compressor to stop, this
function will automatically stop the compressor that started first.
Settings screen related to units control and to compressor
starting order compression
See
"How to change settings in the touch panel" on page 15
change the settings.
When "UNITS TO CONTROL" is set to "1UNIT"
In this case, only the compressor selected in "MOTOR FOR 1 UNIT"
operates.
This function is useful for energy saving operation when the cooling
load is low, like in intermediate season or for emergency operation
should one compressor get out of order.
2-temperature setting function (Optional)
For this model, setting of 2 target temperatures is available on
condition that switching of target temperatures of the unit is available.
We distinguish target temperature for thermal storage mode and for
cooling mode.
The unit performs automatic capacity control in function of the target
temperature of the requested mode.
Screen related to 2-temperature setting
1
Set the current demand percentage (relative to the reference
current value). The default setting=100%.
If you want to set the upper limit operating current to value C,
C=2xA1xB
A1=reference current per compressor as in
B=the current demand setpoint (%)
See
"How to determine the current demand setpoint" on page 24
.
NOTE
■
This is the screen of models with the 2-temperature
setting option. For standard models, the target
temperature is represented by one line only.
■
Touching any of the items will display a brief
explanation on the item (except for the target
temperature).
1
1
2
1
["MENU"
➞
"SETTING"
➞
"SETTING (2/2)"]
When “UNITS TO CONTROL” is set to "1UNIT", this control does
not work. The default setting is "2UNITS".
2
At the first start after power-up, the compressor set in the leftmost
field starts first.
Compressor "1" means the compressor at left side viewed from
the door of the switch box and "2" means the compressor at right
side.
NOTE
Touching any of the items will display a brief
explanation on the item.
1
When "REMOTE" is selected through "MENU"
➞
"OPERATION".
2
When "LOCAL" is selected through "MENU"
➞
"OPERATION",
the unit operates under the mode that corresponds to the mode
button selection on the touch panel.
NOTE
Change of this setting is not available while
the unit is operating.
NOTE
Change of this setting is not available while
the unit is operating.
2
2
2
1
501
54
Cooling mode
Thermal storage mode
Operation is performed
under the mode as set by
the external signal
between terminals 501
to 54.
NOTE
Mode button on the graphic panel display is
ineffective.