York YK M3 M3 G4 THRU YK S6 S4 J2, YK LB LB G4 THRU YK SE SC J4 operation manual Chiller Operation

START-UP

1.If the chilled water pump is manually operated, start the pump. The Control Center will not allow the chiller to start unless chilled liquid flow is es- tablished through the unit. (A field supplied chilled water flow switch is required.) If the chilled liquid pump is wired to the MicroComputer Control Cen- ter the pump will automatically start, therefore, this step is not necessary.

2.To start the chiller, press the COMPRESSOR START switch. This switch will automatically spring return to the RUN position. (If the unit was previ- ously started, press the STOP/RESET side of the COMPRESSOR switch and then press the START side of the switch to start the chiller.) When the start switch is energized, the Control Center is placed in an operating mode and any malfunction will be noted by messages on the 40 character alphanumeric display. (See Fig. 3.)

NOTE: Any malfunctions which occur during STOP/RESET are also displayed.

When the chiller is shut down, the prerotation vanes will close automatically to prevent loading the com- pressor on start-up. When the prerotation vanes are fully closed the “Display” will read

SYSTEM READY TO START – VANES CLOSED when in SERVICE mode.

When the chiller starts to operate, the following auto- matic sequences are initiated: (Refer to Fig. 15, “Chiller Starting & Shutdown Sequence Chart”.)

1.The MicroComputer Control center alphanumeric display message will read

START SEQUENCE INITIATED

for the first 50 seconds of the starting sequence, (3 minutes if Micro Board JP6 removed).

2.The compressor vent line solenoid valve will open after the first 5.83 minutes of operation. The sole- noid will close automatically after the compressor shuts down.

3.The 1R-1 contacts of the 1R start relay will re- main open for the first 50 seconds of oil pump operation. These contacts will close, starting the compressor motor and the condenser water pump at the end of the 50 second period.

4.The oil pump will start to circulate oil for a 50 second pre-run to establish oil flow and adequate lubrication to all bearings, gears, and rotating sur- faces within the compressor.

FORM 160.49-O2

The high and low oil pressure transducers (OP) and the oil temperature sensor (RT3) will sense any malfunction in the lubrication system and ac- tivate one of the following display messages:

DAY 10:30 AM – LOW OIL PRESSURE

DAY 10:30 AM – HIGH OIL TEMPERATURE

DAY 10:30 AM – LOW OIL TEMP – AUTOSTART

DAY 11:30 AM – OIL PRESSURE TRANSDUCER

5.The anti-recycle timer software function will oper- ate after the 50 seconds of pre-run time. At this time, the timer will be initiated and will run for 30 minutes after the compressor starts. If the chiller shuts down during this period of time, it cannot be started until the timer completes the 30 minute cycle.

6.The chilled liquid pump contacts will close start- ing the chilled liquid pump to allow liquid flow through the cooler when the COMPRESSOR start switch is energized.

7.After the first 50 seconds of operation, the com- pressor will start and the Control Center display message will read

SYSTEM RUN – CURRENT LIMIT IN EFFECT while the motor is accelerating to full speed. When the mo- tor reaches full speed and the current falls below 100% FLA the message will read

SYSTEM RUN – LEAVING TEMP. CONTROL

8.For additional display messages and information pertaining to the operation of the MicroComputer Control Center, refer to “Section 2”.

9.Low Oil Temp. Differential.

CHILLER OPERATION

After the compressor reaches its operating speed, the Prerotation Vanes will begin to open under the control of the Microprocessor Board which senses the leaving chilled liquid temperature. The unit capacity will vary to maintain the leaving CHILLED LIQUID TEMPERA- TURE setpoint. The Prerotation Vanes are modulated by an actuator under the control of the Microprocessor Board. The vane control routine employs proportional plus derivative (rate) control action. A drop in chilled liquid temperature will cause the actuator to close the Prerotation Vanes to decrease chiller capacity. When the chilled liquid temperature rises, the actuator will open the Prerotation Vanes to increase the capacity of the chiller.

YORK INTERNATIONAL 31