Technical data

6 OPERATION
If the oil heater is de-energised during a
shutdown period, it must be energized for 24
hours prior to starting the compressor.
6.1 General
YR chillers are designed to work independently, or in
conjunction with other equipment via a York ISN building
management system or other automated control
system. The compressor can be started and loaded as
required using a range or input signals to achieve the
desired cooling effect. This section describes the normal
procedures for operation of the unit and should be read
in conjunction with the control panel Operation
Instruction.
6.2 Pre-Startup
Prior to starting the chiller, observe the control panel.
Make sure the display reads SYSTEM READY TO
START.
The internal clock, all the control setpoints and any other
required settings, eg., daily schedule, should be
programmed before the unit is started. (Refer to control
panel Operation Instruction).
If the chilled water pump is manually operated, start the
pump, the control panel will not allow the unit to start
unless chilled liquid flow is established through the unit.
If the chilled liquid pump is wired to the control panel the
pump will automatically start.
6.3 Start-up (Refer to Figure 6.1)
1. To start the chiller, press the compressor START
switch. This switch will automatically spring return
to the RUN position. When the start switch is
energised, the control panel is placed in an
operating mode and any fault will be shown by a
display message.
Any faults which occur during STOP/RESET
are also displayed.
The slide valve is returned to the unload
position automatically when the unit is shut
down to prevent loading the compressor on
start-up.
When the unit starts, the following automatic sequences
are initiated: (Refer to Figure 6.1 Starting & Shutdown
Sequence).
1. The control panel display message will read
START SEQUENCE INITIATED for the starting
sequence.
2. The measured oil and evaporator pressures are
compared during system equalization so that any
offset is stored for use in calculating deferential trip
points during compressor operation.
160.81-ICOM-GB0 (01/02) 6-1
Figure 6.1 Starting and Shutdown Sequence