OMM 1008-1
9
Control Panel
Figure 2, Control Panel
The unit controller, the OITS microprocessor, the unit and compressor on/off switches and other minor
components are mounted in the control panel. The switches are designated “I” for on and “0” for off. The
compressor on/off switch should only be used when an immediate stop is required since the normal shut
down sequence is bypassed.
The switch panel also has a circuit breaker that interrupts power to the cooling tower fans, valves, and
evaporator and condenser pumps, if any of these are tied into the MicroTech II controller for control of their
operation. If these components operate independently from the chiller control, the breaker has no effect.
The unit controller's function is acquiring and processing data relating to the chiller operation and issueing
instructions to various components to maintain controlled operation. The unit controller also sends
information to the OITS for graphic display. The controller has a 4x20 LCD display and keys for accessing
data and changing setpoints. If the OITS should become inoperable.The controller LCD can display most of
the same information as the OITS and can operate the chiller independently if the OITS is not available.
Emergency
Shutdown Switch,
Outside Panel
Terminal Board
TB UTB1 for Field
Wiring Connections
Controller
OITS PC
Universal
Communication
Module
Field Wiring Knockouts
On/Off
Switches
UNIT
COMP #1
COMP #2
Comp #2 I/O
Comp #1 I/O
EXV Board
