York MILLENNIUM YK, Operating & Maintenance, Page: 19 / 60

FORM 160.52-O1
19
YORK INTERNATIONAL
The Service keys are provided for the service techni-
cian’s use when performing routine maintenance or
when troubleshooting the system. The WARNING RE-
SET and PRE-ROTATION VANES keys are enabled
in SERVICE mode only. The remainder of the Service
keys are enabled in SERVICE , LOCAL or REMOTE
mode.
PRE-ROTATION VANES KEYS
PRE-ROTATION VANES/REFRIGERANT LEVEL
CONTROL/MANUAL SPEED CONTROL – The pre-ro-
tation vanes keys can be used to manually control the
refrigerant level variable orifice, manually control the
oil pump speed or manually control the pre-rotation
vanes. The procedure to select either manual vane,
manual oil pump speed or manual variable orifice con-
trol is contained in “Special Setpoints and Program-
ming Procedures” section of Service manual, Form
160.49-M2 and must be performed by a qualified ser-
vice technician only.
1. Manual Vane Control:
OPEN – Press and release this key to drive the pre-
rotation vanes open. If the chiller is running,
SYSTEM RUN – VANES OPENING
is displayed. If chiller is
not running,
SYS READY TO START – VANES OPENING
is
displayed. The vanes will continue to open until the
CLOSE , HOLD , or AUTO (if temperature error requires
it) keys are pressed and released.
FIG. 13 – KEYPAD – SERVICE KEYS LOCATION
SERVICE KEYS
LD00963
HOLD – Press and release this key to hold the pre-
rotation vanes in their present position. If the chiller is
running,
SYSTEM RUN – VANES HOLDING
is displayed.
If chiller is not running,
SYS READY TO START – VANES HOLDING
is displayed.
The vanes will remain stationary until the OPEN , HOLD ,
or AUTO keys are pressed and released.
CLOSE – Press and release this key to drive the pre-
rotation vanes closed. If the chiller is running,
SYSTEM RUN – VANES CLOSING
is displayed. If chiller is
not running,
SYS READY TO START – VANES CLOSING
is
displayed. When the vanes are full closed,
SYS READY TO START – VANES CLOSED
is displayed.
The vanes will continue to close until the OPEN , HOLD ,
or AUTO keys are pressed.
AUTO – Press and release this key to put the pre-rota-
tion vanes under LCWT control as long as the current
limit setpoint is not reached, which causes the current
limit function to override the LCWT control. If system is
running,
SYSTEM RUN – AUTO VANES
is displayed. The
actual opening and closing of the vanes is indicated on
the display. When the vanes are opening,
SYSTEM RUN – VANES OPENING
is displayed. If the vanes
are closing,
SYSTEM RUN – VANES CLOSING
is displayed.
Whenever the Control Center is in LOCAL , REMOTE
or PROGRAM mode, the vane control circuitry is auto-
matically placed in AUTO mode and the vanes oper-
ate to control the leaving chilled water temperature to
the programmed setpoint.