Unit installation
Table Of Contents
- Introduction
- Installation
- Physical Data
- Electrical Data
- Dimensional Data
- Startup
- Operation
- Global UNT Controller Installation and Operation
- General Description
- Optional Sensors
- Sensors and Transducers
- Control Wiring
- External Voltage Inputs
- Interlock Wiring
- Unit Set Points and Calibration
- Optional Sensors
- Field Wiring
- Power Wiring
- Power Supplies
- Analog input signals
- Digital input signals
- Remote Stop/Start
- Chilled Water Flow Switch
- Digital Outputs
- External Alarm Annunciator Circuitry
- PC Connection
- Software Identification
- Controller Inputs /Outputs
- Additional Global UNT Features
- Alarms
- Zone Terminal (Optional)
- Zone Terminal Glossary
- UNT Troubleshooting Chart
- MicroTech Controller Installation and Operation
- Sensors and transducers
- Control wiring
- Remote 4-20 milliamp signals
- Interlock wiring
- Unit set points and calibration
- Modem kit
- Lead-Lag
- Field Wiring
- Power Wiring
- Power Supplies
- Analog Input Signals
- Digital Input Signals
- Remote Stop/Start
- Chilled Water Flow Switch
- Digital Outputs
- Chilled Water Pump Relay
- External Alarm Annunciator Circuitry
- PC Connection
- Telephone line
- Software Identification
- Controller Inputs /Outputs
- Reset Options
- Soft Loading
- Manual Operation
- Compressor Staging
- Head Pressure Control
- Pumpdown Control
- Safety Systems
- Circuit Alarm Conditions
- System Alarm Conditions
- Sequence of Operation
- Start-Up and Shutdown
- Keypad / Display
- Menu Descriptions
- Trouble Analysis for the MicroTech
- Test Procedures
- Unit Maintenance
- Service
IOMM AGZ-3 AGZ 035A through 065A 3
Introduction
General Description
McQuay Air-Cooled Global water chillers are complete, self-contained automatic refrigerating units.
Every unit is completely assembled, factory wired, charged, and tested. Each unit consists of twin air-
cooled condensers with integral subcooler sections, two tandem scroll compressors, replaceable tube,
dual circuit shell-and-tube evaporator, and complete refrigerant piping. Liquid line components
include manual liquid line shutoff valves, sight-glass/moisture indicators, solenoid valves, and double
diaphragm hydraulic element thermal expansion valves. Other features include compressor crankcase
heaters, an evaporator heater for chilled water freeze protection, limited pumpdown during “on” or
“off” periods, compressor lead-lag switch to alternate the compressor starting sequence, and
sequenced starting of compressors.
The electrical control center includes all equipment protection and operating controls necessary for
dependable automatic operation. Condenser fan motors are fused in all three phases and started by
their own three-pole contactors. Compressors are not fused but may be protected by optional circuit
breakers.
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 13.
Nomenclature
A G Z - XXX A S
Air-Cooled
Global
Scroll Compressor
Desi
g
n Vinta
g
e
Model Size
(Nominal Tons)
Application
S= Standard Cooling