Technical data

3. The chilled liquid pump contacts close starting the
chilled liquid pump to allow liquid flow through the
evaporator. The chilled water flow switch is
bypassed until the last 5 seconds of the start
sequence.
4. After T seconds of start sequence operation, the
compressor will start.
5. When the motor reaches full speed and the current
falls below 100% FLA the message will read:
LEAVING CHILLED LIQUID CONTROL.
6. The anti-recycle timer begins after 30 seconds of
the start sequence initiated time. The timer will run
for 30 minutes after the compressor starts. If the
unit shuts down during this period of time it cannot
be started until the timer completes the 30 minute
cycle.
For display messages and information
pertaining to operation, refer to the control
panel Operating Instruction.
6.4 Normal Operation
After the compressor reaches its operating speed the
slide valve will begin to load, under the control of the
control panel, based on the leaving chilled liquid
temperature. The unit capacity will vary to maintain the
leaving chilled liquid temperature at the programmed
setpoint. A drop in chilled liquid temperature will cause
the slide valve to unload to decrease unit capacity.When
the chilled liquid temperature rises, the slide valve loads
the compressor and increases the unit capacity.
The compressor motor current will be limited to a
programmable maximum during the unit operation. The
control panel can be programmed in various ways to
limit the motor current to between 30 and 100% of Full
Load Current as required (see the control panel
Operation Instruction for more details).
While the compressor is running a wide variety of
system parameters are monitored automatically by the
control panel. These can be accessed and displayed as
required via the control panel keypad and display. If any
problems are detected the cause will be shown on the
display and the appropriate action will be taken, eg
reducing slide valve loading, giving a warning message,
or shutting down the unit.
6.5 Shutdown
During normal operation the unit may shut down for a
number of reasons such as low load, scheduled daily
shutdowns and multi unit cycling. In each case the
control panel display will indicate the reason for the
shutdown. For example, if during operation the control
panel has unloaded the compressor completely and
load continues to fall, the unit will be shut down and the
display will read: LEAVING CHILLED LIQUID
CONTROL - LOW TEMPERATURE.
If the unit is shut down because a problem has been
detected by the control panel, a similar type of message
will be displayed indicating the nature of the problem
(see control panel Operation Instruction, for more
information).
When the unit is shutdown, the slide valve will close
automatically to minimise load on the compressor motor
during startup. A minimum of two minutes after
shutdown is required for system pressure equalisation
before the compressor will be allowed to restart.
6.6 Manual Shutdown
To stop the unit manually:
1. Press the compressor STOP/RESET switch. The
control panel display will show: SYSTEM
LOCKOUT DELAY. This prevents compressor
restart until system equalization is achieved.
2. Stop the chilled water pump (if not wired into the
control panel, in which case it will shut off
automatically.)
3. Open the switch to the cooling tower fan motors, if
used.
The compressor sump oil heater
(thermostatically controlled) is energised
when the unit is stopped.
6-2 160.81-ICOM-GB0 (01/02)