FORM 201.24-NM2
35
YORK INTERNATIONAL
mote run interlocks are in the run position and that the
run schedule requires the unit to run or is overridden.
System switches: Set the system 1 switch on the mi-
croprocessor board to the ‘ON’ position – see operat-
ing sequence in the MBCS Section.
Start-up: Press the ‘STATUS’ key, and set the toggle
switch to the ‘ON’ position to start the unit (there may
be a few seconds delay before the first compressor starts
because of the anti-recycle timer). Be ready when each
compressor starts, to switch the unit off immediately if
any unusual noises or other adverse conditions develop.
Use the emergency stop device if necessary. Also refer
to the MBCS Section for the normal operating sequence
from start-up.
Oil Pressure: When a compressor starts, press the rel-
evant ‘SYSTEM DATA’ key and verify that oil differ-
ential pressure develops immediately. If oil pressure
does not develop, the automatic CONTROLS WILL
shut down the compressor. Under no circumstances
should a restart attempt be made on a compressor which
does not develop oil pressure immediately.
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.
Suction Superheat: Check suction superheat at steady
full compressor load only. It is important that no bubbles
show in the liquid line sight glass. Superheat should be
4°C to 5°C relative to the ‘dew’ temperature.
Expansion Valve Adjustment: The expansion valves
are factory set and should not need adjustment. If any
superheat values are out of range, however, the expan-
sion valve adjusting screw should be adjusted no more
than 1 turn at a time (‘in’ to increase superheat, ‘out’
to decrease superheat), allowing at least 10 minutes
for the valve to stabilize before rechecking the value
of superheat.
Subcooling: Check liquid subcooling at steady full
compressor load only. It is important that cooling sys-
tem is operating correctly. Subcooling should be 5°C
to 7°C relative to the ’bubble’ temperature.
General Operation: After completion of the above
checks for system 1 repeat the process for system 2.
When the checks are complete stop the unit, switch
both system switches to the ‘ON’ position and restart
the unit. Check that loading occurs as specified in the
MBCS and that general operation is correct.
5
Summary of Contents for YCWS0313SC
Page 12: ...YORK INTERNATIONAL 12 THIS PAGE INTENTIONALLY LEFT BLANK TO MAINTAIN PAGE FORMAT...
Page 36: ...YORK INTERNATIONAL 36 THIS PAGE INTENTIONALLY LEFT BLANK TO MAINTAIN PAGE FORMAT Commissioning...
Page 86: ...YORK INTERNATIONAL 86 TYPICAL CONTROL PANEL WIRING Maintenance...
Page 87: ...FORM 201 24 NM2 87 YORK INTERNATIONAL TYPICAL CONTROL PANEL WIRING LD06957 8...
Page 103: ...FORM 201 24 NM2 103 YORK INTERNATIONAL NOTES 11...