EWWD440~850AAYNNO**
Packaged water-cooled water chillers
4PW25558-1B
Installation and operation manual
27
Starting time chart of the compressor
“UNITS TO CONTROL” is set to “2UNITS”
“UNITS TO CONTROL” is set to “1UNIT”
Water temperature control immediately after unit start
For preventing to frequent running and stopping of the unit during the
first 10 minutes after the unit start (low holding water quantity or low
load), the unit performs a step-by-step reading of the target
temperature.
Only after elapse of these 10 minutes, operation shifts to automatic
capacity control in function of the set target temperature.
NOTE
1.
If the compressor load is not 0% at starting, the close
command is output to the capacity control motor for
160 seconds maximum. If it is not 0% after 160
seconds, the potentiometer of the target compressor
(1 or 2) confirms a full-shut error (compressor
individual error).
2.
If the interlock contact does not turn ON within 180
seconds after the pump operation command is output
from the unit (88WEX, 88WCX), the pump interlock
error is confirmed (unit error).
3.
For ensuring an early differential pressure for
obtaining cooling stability of the compressor motor
and oil supply to respective parts of the compressor,
the compressor load increases up to 45% forcedly.
1
Compressor ON
2
Compressor load down
3
Compressor load up
4
Load down without use of timer (forced load down)
Forced load up to the opening limitation without use of timer
Start of automatic capacity control
1
2
3
2
3
1
4
4
15 sec
15 sec
3 sec
ON
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
Compressor to star
t first
Bac
k-up compressor
1
Compressor ON
2
Compressor load down
3
Compressor load up
4
Load down without use of timer (forced load down)
Forced load up to the opening limitation without use of timer
Start of automatic capacity control
1
Unit stop
2
Unit operation
3
Target temperature as set on the control panel
4
Target tempe2°C
15 sec
3 sec
1
2
3
4
ON
OFF
OFF
ON
4
3
1
2
10 min
