Operating instructions

Optional Features
Any of the following options can be included on a unit:
Controls
Hot Gas Bypass
Hot gas bypass permits unit operation down to 10% of full load capacity. This option includes a
factory-mounted hot gas bypass valve, solenoid valve, and manual shutoff valve for each circuit.
Head Pressure Control
Fan VFD low ambient control allows unit operation down to 0°F (-18°C). (Not available on 380
volt, 60 Hertz units.)
Water Flow Switch (AGZ-BM only)
(P/N 017503300) A water flow switch is available for field installation in the chilled water piping to
avoid evaporator freeze-up under low or no flow conditions. Terminals are provided in the unit
control center for field hook-up of the water flow switch. If this option is not ordered with the unit,
then a field supplied water flow switch must be installed.
Alarm Bell
Field-installed and wired to the control panel to provide remote indication of unit alarm condition.
See Field Wiring Diagram for connection locations.
BAS Interface (Protocol Selectability™ Feature)
Connection to Chiller
Connection to the chiller for all Building Automation System (BAS) protocols will be at the unit
controller. An interface card, depending on the protocol being used, can be factory-installed in the
unit controller (or it can be field-installed).
Protocols Supported
Table 37, Standard Protocol Data
Protocol Physical Layer Data Rate Controller Other
®
Reference ED 15057:
BACnet PICS
BACnet /IP or
BACnet/Ethernet
Ethernet 10 Base-T 10 Megabits/sec
pCO
2
Unit Controller
BACnet MSTP RS-485 (TBD)
pCO
2
Reference ED 15057:
BACnet PICS
Unit Controller
®
L
ONMARK Chiller
Functional Profile
LONWORKS
®
FTT-10A 78kbits/sec
pCO
2
Unit Controller
Modbus RTU? RS-485or RS-232 (TBD)
pCO
2
Unit Controller
Note: For additional information on the protocol data available through the BACnet or
LONWORKS communications modules reference ED 15062, MicroTech II Chiller Unit Controller
Protocol Information.
Modbus – When selected, the ident number and baud rate can also be changed to suit the application.
L
ONWORKS – When selected, the ident number and baud rate setpoints are not available. Baud rate
is locked at 4800.
BACnet – When selected, the ident number and baud rate setpoints are not available. Baud rate is
locked at 19200.
56 ACZ / AGZ-BM IMM ACZ/AGZ-4