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

68 AGZ 035A through 065A IOMM AGZ-3
Menu #6: Circuit 62 PressuresThe circuit #2 evaporator and condenser refrigerant pressure
readings are displayed under this menu. The calculated minimum and maximum condenser pressure
values are also shown.
Menu #7: Circuit #l TemperaturesThe circuit #I refrigerant temperatures are calculated from their
corresponding pressure sensors and displayed here. If the optional Sensors are not present, the line
item will flash “Open”.
Menu #8: Circuit #2 TemperaturesThe circuit #2 refrigerant temperatures are calculated from their
corresponding pressure sensors and displayed here. If the optional sensors are not present, the line
item will flash “Open”.
Menu#9: Chiller AmpsDisplays the present amp draw of the chiller expressed as a percentage of
the unit rated load amps under full load conditions (optional feature).
Menu #10: Compressor Run HoursThe total run hours for each compressor is available under this
menu.
Menu #11: Compressor StartsThe total number of starts for each compressor is available under this
menu.
Menu#12: Air TemperatureDisplays the current outdoor air temperature if the optional OAT sensor
is installed on the air cooled chiller and “Lcl” is selected from Menu 23. Also displayed here is the
air temperature received from a network if the “Rmt” OAT select option from Menu 23 is selected.
Control Menus
Menus 13 through 23 are the set point menus. All adjustable control parameters and set points, time
schedules, control options, and alarm thresholds are accessed through these menus.
CAUTION
Any changes to these parameters must be determined and implemented by
qualified personnel with a thorough understanding of how these parameters
affect the operation of the unit. Negligent or improper adjustment of these
controls can result in damage to the unit or personal injury.
Menu #13: Control ModeOne of several automatic and manual operating modes can be selected
from within this menu. Typically, the selected control mode will be Automatic which will allow the
MicroTech controller to handle all compressor and condenser fan staging. Refrigerant circuit #2 can
be locked off while still allowing circuit #1 to stage automatically by selecting AutoCir#1 -Off#2 as
the operating mode. OffCirc#1 -Auto#2 allows the normal staging of refrigerant circuit #2 but circuit
#1 is locked off. Select Manual Staging if manual control is desired. In this operating mode, the
condenser fans are controlled by the MicroTech but the number of stages is determined manually via
the keypad. If manual staging is selected, the second item under this menu indicates the number of
active cooling stages. Use the INCR or DECR keys to increase or decrease the number of active
stages.
Menu#14: Leaving Water Set PointsThe leaving wafer set points, control band, maximum pull
down rate and water reset options are adjusted from this menu. The first menu item is The Active Set
Point ("Active Spt"). The current control temperature is displayed here. The Leaving Chilled Water
Set Point ("Lvg Evap") appear towards the top of this menu. These are the set points that will be
maintained for chillers if no reset options are in effect. The Active Control Set Point ("Active Spt")
will display the calculated chilled or heated water temperature to be maintained when one of the reset
options is enabled.
If the 4-20 milliamp reset option is enabled, the controller will reset the leaving chilled water
temperature to a higher value based on a percentage of the Maximum Chilled Water Reset set point
("MaxChWRst"). At 4ma or less, no reset will occur. At 20ma, the chilled water set point will be reset