Operating instructions

54 IMM AGSB-60
Start-up and Shutdown
NOTICE
McQuayService personnel or factory authorized service agency
must perform initial start-up in order to activate warranty.
CAUTION
Most relays and terminals in the unit control center are powered when S1
is closed and the control circuit disconnect is on. Therefore, do not close S1
until ready for start-up or the unit may start unintentionally.
Switches
There is a single unit on-off switch, S1, located in the control box for circuit #1. S1 will cause
a rapid shutdown, without pumpdown, when opened. The circuit #1 box and all other control
boxes also have a circuit switch, CS, which will put the circuit into pumpdown when put in the
open position. The (1) on the switch is on and the (0) is off.
Seasonal Start-up
1. Double check that the optional compressor suction butterfly valve is open.
2. Check that the manual liquid-line shutoff valves at the outlet of the subcooler coils are
open.
3. Check the leaving chilled water temperature setpoint on the MicroTech II controller to be
sure it is set at the desired chilled water temperature.
4. Start the auxiliary equipment for the installation by turning on the time clock, and/or
remote on/off switch, and chilled water pump.
5. Check to see that circuit switches, CS, are in the off position. Put the unit switch, S1, in
the on position.
6. Under the "Control Mode" menu of the keypad, place the unit into the automatic cool
mode.
7. Start the system by placing the circuit #1 pumpdown switch CS in the on position.
8. Repeat step 7 for the balance of the circuits.
Temporary Shutdown
Move pumpdown switches CS to the off position. After the compressors have pumped down,
turn off the chilled water pump.
CAUTION
Do not turn the unit off using the "S1" switch, without first moving PS1 and PS2
to the off position, unless it is an emergency, as this will prevent the unit from
going through a proper shutdown/pumpdown sequence.