CAUTION
Comply with EPA and local regulations when removing or disposing of refrigeration system oil.
Start-up procedure
Pre-starting
Prior to starting the chiller, observe the Optiview
™
Control Center – Operation Manual (160.76-O2).
Make sure the display reads SYSTEM READY TO START.
CAUTION
Vent any air from the chiller waterboxes prior to starting the water pumps. Failure to do so will result in
pass baffle damage.
Start-up
1. The Start/Stop control is operated via the Soft START button on the Home Screen. When the
user presses the green START button, a dialog box is displayed instructing the user to press
the ENTER button to start the chiller, or to press the CANCEL button to abort the start.
2. When the chiller is running, the Start button is replaced by a red SOFT STOP button. When
the user presses this button, a dialog box is displayed instructing the user to press the ENTER
button to stop the chiller, or the CANCEL button to abort the stop command. The Soft Stop
command drives the PRV closed and then shuts off the chiller.
For display messages and information pertaining to the operation refer to OptiView
™
Control Center
– Operation Manual (160.76-O2).
Note: Any malfunctions that occur during STOP/RESET are also displayed.
Chiller operation
The unit capacity varies to maintain the leaving CHILLED LIQUID TEMPERATURE setpoint by the pre-
rotation vanes, which are modulated by an actuator under the control of the Microprocessor Board.
The vane control routine employs proportional plus derivative (rate) control action. A drop in chilled
liquid temperature causes the actuator to close the pre-rotation vanes to decrease chiller capacity.
When the chilled liquid temperature rises, the actuator opens the pre-rotation vanes to increase the
capacity of the chiller.
However, the current draw (amperes) by the compressor motor is also limited to FLA setpoint by
the microprocessor.
If the load continues to decrease, after the pre-rotation vanes are entirely closed, the chiller is shut
down by the Leaving Chilled Liquid – Low Temperature Control.
The coolant temperature inside any Johnson Controls supplied liquid-cooled motor starter must
be maintained above the dewpoint temperature in the equipment room to prevent condensing
water vapor inside the starter cabinet. Therefore, an additional temperature-controlled throttle
valve is needed in the flow path for the starter heat exchanger to regulate cooling above the
equipment room dewpoint for applications using cooling sources other than evaporative air-
Model YK (Style H), R-134a and R-513A12
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