38
YORK INTERNATIONAL
COMPRESSOR SWITCH/EMERGENCY STOP SWITCH
The following displayed messages will be automatically
displayed unless the operator is requesting additional in-
formation via the keypad.
SYSTEM RUN – LEAVING TEMP CONTROL
Chiller is operating with prerotation vane and engine speed
control in response to leaving chilled water temperature.
Engine loading is less than 98% of operator programmed
load limit.
SYSTEM RUN – ENGINE LOAD LIMIT IN EFFECT
Displayed when the chiller is running, the engine loading
is equal to the operator-programmed XXX% engine load
limit value. When the engine loading reaches 98% of this
value, the prerotation vanes are not permitted to open
further. If the engine loading continues to rise to 102% of
this value, the vanes will be driven closed-not fully closed;
only far enough to allow the engine loading to decrease
to 100% of the operator-programmed XXX% engine load
limit.
For example:
With the operator-programmed
% ENGINE LOAD
LIMIT
set at 50%, the engine load limit circuit would
perform as follows:
( 98%) (50%) = Vanes inhibited from opening further
(102%) (50%) = Vanes driven toward close position
AUTO
SYSTEM RUN – AUTO SPEED/AUTO VANES
SYSTEM RUN – VANES OPENING
SYSTEM RUN – VANES CLOSING
SYSTEM RUN – AUTO SPEED/AUTO VANES
(See Fig. 15, page 32)
This rocker switch is used to locally operate the chiller. It
is used to start, run and stop the compressor. Also, it
resets the Micro Control Center after a safety shutdown.
To
START
* chiller compressor in
LOCAL
mode:
Move
COMPRESSOR
switch from
STOP/RESET
to
START
position. Switch will spring-return to
RUN
position.
*NOTE: The operator cannot start the chiller (using
this switch) when the Control Center is in
REMOTE
mode.
To
STOP
compressor:
Move switch from
RUN
to
STOP/RESET
position.
This will initiate a standard shutdown which
takes sev-
eral minutes to complete
.
To
RESET
Control Center:
Following a safety shutdown, the operator is required to
reset the Control Center prior to restarting the system.
Refer to description on page 13 to reset the system.
Emergency Stop Switch (located on engine
panel:
To perform an emergency stop the red push-
button on the Engine Control Panel (ECP) must be
depressed. This will initiate a quick shutdown of the
system.
This is for emergency shutdowns only.
DISPLAY MESSAGES
SYSTEM RUN - ENGINE LOAD LIMIT IN EFFECT
The previous displays are displayed when the chiller is
running, the MicroComputer is in
SERVICE
mode, and
the vanes are opening in
AUTO
mode.
OPEN
SYSTEM RUN – AUTO SPEED/AUTO VANES
SYSTEM RUN – VANES OPENING
The above displayed when the chiller is running and the
MicroComputer Center is in the
SERVICE
mode and
vane/speed toggle is set for
VANES
.
CLOSE
SYSTEM RUN – AUTO SPEED/AUTO VANES
SYSTEM RUN – VANES CLOSING
The above displayed when the chiller is running, the mi-
crocomputer center is in the
SERVICE
mode, and vane/
speed toggle is set for
VANES
.
HOLD
SYSTEM RUN – AUTO SPEED/AUTO VANES
SYSTEM RUN – VANES HOLDING
The above displayed when the chiller is running, the Mi-
croComputer Center is in the
SERVICE
mode, and vane/
speed toggle is set for
VANES
.
SYSTEM RUN – LOW PRESSURE LIMIT IN EFFECT
Displayed when the chiller is running and the evaporator
pressure falls to 27 PSIG. Simultaneously, the prerotation
vanes will be prevented from further opening and speed
may not be increased. This action maintains chiller op-
= <98%
ENGINE LOAD
Either or switches back
and forth with the above
reading/display of:
ö
ö
ö
= <98%
ENGINE LOAD
= with AUTO
pressed
= with OPEN pressed
= with AUTO
pressed
= with AUTO
pressed
= with CLOSE pressed
= with HOLD pressed
