Unit installation

40 OMRCPMICRO
Powering the control panel
Figure 13, Status LEDs
Status LEDs—There are three Status LEDs located on the
model 250 controller which will indicate the
microprocessor's operating condition. When power is first
applied to the control panel, the red RESET LED will
illuminate for approximately 3 seconds. During this time,
the microprocessor is checking the control software and
performing internal hardware tests. When these tests are
complete the RESET LED will turn off and the green
RUNNING LED will illuminate indicating the controller's
circuitry and software are operating correctly. If the RESET
LED stays on or the RUNNING LED fails to illuminate,
disconnect the controller power by opening circuit breaker
CB-1 and re-check the field wiring. Observe the controller's
LEDs while re-connecting power by closing CB-1.
If the RUNNING LED still does not turn on, refer to the troubleshooting section in this manual. The amber
OUTPUT 0 ACTIVE LED is associated with the external alarm output on the solid-state relay board and will be
illuminated during any alarm conditions. ADI Board LEDs #0, 1, 2, 3, 4, 6, 8, 9, 10, 11, 12 and 13 should be
illuminated at this time and the keypad/display will indicate the unit status as OFF:SYSTEM SWITCH.
Observe the LEDs on the ADI board while manually operating the field mounted devices such as flow
switches to ensure they are connected to the correct terminals.
McQuay chiller and Templifier MicroTech controllers come with factory installed default set points for the
control mode, leaving water temperatures, soft loading, compressor staging, head pressure settings, internal
scheduling, holiday dates and alarm functions. The Control Menus 13 through 22 (Table 8) contain the above
items. The installing contractor should step through all the unit's set points by using the keypad/display and
adjust them as required to meet the job specifications. The default set points should be appropriate for most
common installations. On Menu 13, the control mode is set for a default of "Manual Unit Off". The setting
should be adjusted before unit operation can proceed. Before staging the unit, the user should verify and set
the correct control and safety settings for the application (Menu 22). For further information on the menu
items, refer to the Menu Descriptions section of this manual. Any alarms appearing on the display should be
cleared at this time by pressing the CLEAR key on the keypad/display.
Watch the LEDs on the output board to determine the operating status of the controller's outputs while
performing the following system checks.
Move the System Switch to the Auto position. LED #5 on the ADI Board will turn on and if the internal time
schedule indicates an "on" period, the chilled water pump output will be activated. The keypad/display will
show the unit status as OFF:PumpDnSw's.
Move both Circuit Pumpdown Switches to the auto position. LEDs #7 and 15 on the ADI Board will illuminate.
The controller will verify chilled water flow and both refrigerant circuits will go through a pumpdown sequence
if required. The controller will monitor the water loop temperature and if cooling or heating is required, the lead
compressor will start. The unit will stage up automatically to meet system demand based on the set points
stored in the controller's memory and the keypad/ display will show the unit's current stage. Condenser fans
for the lead refrigerant circuit will be cycled as required to maintain proper condenser pressure. All operating
characteristics will be viewable on the keypad/display.
Temporary shutdown
Move the Circuit#1 and Circuit#2 pumpdown witches to the "Pumpdown and Stop" position. Each circuit will
pumpdown and the compressors will stop. In this condition, the compressors will remain off and no additional
pumpdown will occur even if the evaporator pressure rises above the LPCutIn setpoint.
After both circuits have been pumped down, open the Remote Stop Switch and the controller will stop the
chilled water pump.