Johnson Controls York YCRE 040, Manual

Page: 30 / 68

Cooler and Condenser flow rates and
pressure drops must be within the limits given
in Section 9. Operation outside of these limits
is undesirable and could cause damage.
Flow switch: Verify a chilled liquid flow switch is
correctly fitted in the customer’s pipework on the
evaporator outlet, and wired into the control panel
correctly. On YCSE units verify a cooling liquid flow
switch is fitted in the customer's pipework on the
condenser outlet, and wired into the control panel
correctly.
Control supply : Verify the control panel display is
illuminated.
HP cut-out reset: Check that the hand reset
mechanical high pressure cut-outs mounted on the
compressors are at the correct setting and are reset.
5.2 First Time Start-up
During the commissioning period there should
be sufficient heat load to run the unit under
stable full load operation to enable the unit
controls, and system operation to be set up
correctly and a commissioning log taken.
Interlocks : Verify that liquid is flowing through the
cooler and that heat load is present. Ensure that any
remote run interlocks are in the run position and that the
run schedule requires the unit to run or is overridden.
System configuration : Ensure all DIP switch settings
are correct for system operationand that safety settings
are within the design parameters for the site application.
Start-up: Press the system ON switch SW1 to start the
unit. There will be a delay before the compressor starts.
See the operating sequence chart in Section 6. Be ready
when the compressor starts to switch off the unit
immediately if any unusual noises or other adverse
conditions develop. Use the main ON/OFF switch if
necessary.
Discharge and suction pressures: Check the
discharge and suction pressures on the control panel
display. Refer to Section 6. Check the pressures are in
accordance with the pressure curves given in Section 9.
Superheat temperature : Check the superheat
temperature is in accordance with the temperature
curve given in Section 9.
Sub-cooling temperature: Check the sub-cooling
temperature is in accordance with the temperature
curve given in Section 9.
Refrigerant flow: When a compressor starts a flow of
liquid refrigerant will be seen in the liquid line sight glass.
After several minutes operation and providing a full
charge of refrigerant is in the system, the bubbles will
disappear and be replaced by a solid column of liquid.
Check moisture indicator (if fitted) for correct colour
indication.
Control and protective devices: Check that all the
control and protective devices operate in accordance
with the operation sequence chart in Section 6.
Thermostat: Check the unit responds correctly to
thermostatic demands, remote run demands and
shutdown.
General operation : When the checks are complete,
stop the unit by pressing the system OFF switch SW2. If
the unit is not in remote control mode, restart the unit the
unit by pressing the system ON switch SW1. Check that
loading occurs and that general operation is correct.
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035-21786-100 Rev. 1 (0909)