Operating instructions

Introduction
General Description
This manual covers two similar product lines:
AGZ-BM, Packaged chiller with the evaporator shipped separately for remote installation, field
piping to the outdoor unit, and interconnection of wiring. The refrigeration specialties are shipped
from the factory for field installation.
Operating instructions are contained in operating manual OM AGZ.
ACZ-BC, Condensing unit with no evaporator included. For use with customer supplied low side
(usually an air-handling unit), field piped and wired to the condensing unit.
Operating instructions are contained in operating manual OM ACZ.
These McQuay air-cooled units are complete, self-contained, automatic refrigerating units. Every
unit is completely assembled, factory wired, tested and provided with a holding charge. Each unit
consists of two air-cooled condenser sections with integral subcooler sections, two tandem or triple
scroll compressors, (brazed-plate or replaceable tube, dual circuit shell-and-tube evaporator and
liquid line components including manual, sight-glass/moisture indicators, solenoid valves, and
thermal expansion valves on AGZ-BM only). Other features include compressor crankcase heaters,
an evaporator heater for chilled water freeze protection (on AGZ-BM only), one-time pumpdown
during “on” or “off” periods, and automatic compressor lead-lag to alternate the compressor starting
sequence.
The electrical control center includes all equipment protection and operating controls necessary for
dependable automatic operation. Condenser fan motors are protected in all three phases and started
by their own three-pole contactors. Model ACZ condensing units require a field-supplied multi-step
thermostat wired to the outdoor unit.
Inspection
Check all items carefully against the bill of lading. Inspect all units for damage upon arrival. Report
shipping damage and file a claim with the carrier. Check the unit nameplate before unloading,
making certain it agrees with the power supply available. McQuay is not responsible for physical
damage after unit leaves the factory.
Note: Unit shipping and operating weights are available in the Physical Data tables
beginning on page 28.
Nomenclature
A G Z - XXX B M
Air-Cooled
Application
C= Condensing Unit
M= Remote Evaporator
G=Global Chiller
Design Vintage
C=Condensing Unit
Model Size
Scroll Compressor
(Nominal Tons)
IMM ACZ/AGZ-4 ACZ / AGZ-BM 3