York Millennium YK M3 M3 G4 THRU YK S6 S4 J2 - Manual (Page 19)

YORK INTERNATIONAL 19
FORM 160.49-O2
FIG. 13 – KEYPAD – SERVICE KEYS LOCATION
The Service keys are provided for the service techni-
cian’s use when performing routine maintenance or when
troubleshooting the system. The WARNING RESET and
PRE-ROTATION VANES keys are enabled in SERVICE
mode only. The remainder of the Service keys are en-
abled in SERVICE, LOCAL or REMOTE mode.
PRE-ROTATION VANES KEYS
If chiller is equipped with the REFRIGERANT LEVEL
CONTROL (and EPROM version C.02F(T).13 or later),
the pre-rotation vanes keys can be used to manually
control the refrigerant level variable orifice or the pre-
rotation vanes. The procedure to select either manual
vane or manual variable orifice control is contained in
“Special Setpoints and Programming Procedures” sec-
tion of Service manual, Form 160.49-M3 and must be
performed by a qualified service technician only.
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.
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.
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 automati-
cally placed in AUTO mode and the vanes operate to
control the leaving chilled water temperature to the pro-
grammed setpoint.
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.
SERVICE KEYS
LD00963