Specifications

when it is under control from a remote switch or BAS. When these buttons are pressed, the unit will cycle
through its normal starting or stopping sequence, both compressors will be stopped and normal dual
compressor starting procedure will be in effect.
2. Remote SWITCH, Selecting SWITCH in SP3 will put the unit under the control of a remote switch that
must be wired into the control. See Field Wiring Diagram, page 23.
3. BAS, BAS input is field-wired into a communication module that is factory-installed on the unit controller.
4. Control Panel Switches
Three On/Off switches are located in the upper left corner of the main Control Panel, which is adjacent to
the operator interface panel, and have the following function:
• UNIT shuts down the chiller through the normal shutdown cycle of unloading the compressors.
• COMPRESSOR one switch for each compressor on the unit, executes an immediate shutdown without
the normal shutdown cycle.
• CIRCUIT BREAKER disconnects optional external power to system pumps and tower fans.
A fourth switch located on the left outside of the Unit Control Panel and labeled EMERGENCY STOP
SWITCH stops the compressor immediately. It is wired in series with the COMPRESSOR On/Off switches.
Annual Unit Startup/Shutdown
Annual Shutdown
Where the chiller can be subject to freezing temperatures, the condenser and chiller must be drained of all water.
Dry air blown through the condenser will aid in forcing all water out. Removal of condenser heads is also
recommended. The condenser and evaporator are not self-draining and tubes must be blown out. Water
permitted to remain in the piping and vessels can rupture these parts if subjected to freezing temperature.
Forced circulation of antifreeze through the water circuits is one method of avoiding freeze up.
1. Take measures to prevent the shutoff valve in the water supply line from being accidentally turned on.
2. If a cooling tower is used and if the water pump will be exposed to freezing temperatures, be sure to remove
the pump drain plug and leave it out so any water that can accumulate will drain away.
3. Open the compressor disconnect switch. Set the manual COMPRESSOR and UNIT ON/OFF switches in
the Unit Control Panel to the OFF position.
4. Check for corrosion and clean and paint rusted surfaces.
5. Clean and flush water tower for all units operating on a water tower.
6. Remove condenser heads at least once a year to inspect the condenser tubes and clean if required.
Annual Startup
1. Check and tighten all electrical connections.
2. Replace the drain plug in the cooling tower pump if it was removed at shutdown time the previous season.
3. Install fuses in main disconnect switch (if removed).
4. Reconnect water lines and turn on supply water. Flush condenser and check for leaks.