York YK M3 M3 G4 operation manual is displayed, To Display MOTOR CURRENT, System Setpoints

To Display CONDENSER LIQUID TEMPERATURES (Field Installed Option Package):

Use CONDENSER LIQUID TEMPS display key as described above to produce the following alphanu- meric display message:

COND LEAVING = XXX.X°F; RETURN = XXX.X°F

NOTE: If the condenser liquid thermistors are not con- nected, or both thermistors are “out of range”, the display will blank when this key is pressed.

To Initiate a PRINT to Printer:

Press the PRINT key to initiate a printout to an op- tional printer. When the key is pressed,

PRINT ENABLE is displayed.

Refer to “MicroComputer Control Center – System Status Printers” instruction, Form 160.49-N7 for de- tails of the optional printers.

To Display MOTOR CURRENT:

Press the % MOTOR CURRENT display key as described above to display motor current as a per- cent of Full Load Amps (FLA). The message is as follows:

MOTOR CURRENT = XXX% FLA

NOTE: • Liquid-Cooled Solid State Starter Applications

–the % Motor Current displayed is the highest of three line currents divided by the programmed chiller FLA value x 100%.

•Electro-Mechanical Starter Applications – the % Motor Current displayed is the highest of the three line currents.

To Display OPERATING HOURS and STARTS COUNTER:

Use the OPERATING HOURS key as described on page 8, to produce the following message:

OPER. HOURS = XXXXX; START COUNTER = XXXXX

NOTE: The operating hours and starts counter can be reset to zero. Refer to “Programming the Micro-

Computer Control Center”, page 14. However, the purpose of the OPERATING HOURS key is to display the total accumulated chiller run time. Therefore, the operating hours should not be arbitrarily reset.

SYSTEM SETPOINTS

The system setpoints may be programmed by the sys- tem operator. The Setpoints keys are located on the Control Center keypad (see Fig. 3).To program, see “Pro- gramming System Setpoints”, page 14. The following is a description of these setpoints (with the English/ Metric jumper installed on the Micro Board):

CHILLED LIQUID TEMP – This key displays the leav- ing chilled water temperature (LCWT) setpoint in degrees Fahrenheit. If not programmed, the default value is 45°F. See “Programming System Setpoints”, page 15).

NOTE: If an Energy Management System is interfaced to the Control Center for the purpose of remote LCWT setpoint reset, then the operator-pro- grammed chilled liquid temperature will be the base or lowest setpoint available to the Energy Management System (EMS). This chilled liquid temperature value must also be entered into the EMS. Further, any subsequent change to this value must also be entered into the EMS.

%CURRENT LIMIT – This key displays the maximum value of motor current permitted by its programmed set- ting. The value is in terms of percent of Full Load Amps (FLA). If not programmed, the default value is 100%. (See “Programming System Setpoints”, page 15.)

If chiller is equipped with a YORK Solid State Starter, the system FLA is also displayed. This value is pro- grammed by the factory and should never be changed. The Micro Board uses this value to calculate and dis- play the % motor current parameter that is displayed when the % MOTOR CURRENT display key is pressed. Also, proper current limit control depends on the cor- rectly programmed FLA value. For security reasons, a special access code is required to program the FLA value. It should only be changed by a service technician.

PULL DOWN DEMAND – This function is used to pro- vide energy savings following the chiller start-up. This key displays a programmable motor current limit and a programmable period of time. Operation is as follows: Whenever the system starts, the Pull Down Demand Limit is maintained for the programmed time, then the current limit control returns to % current limit setpoint. The maximum permitted motor current is in terms of % FLA. The duration of time that the current is limited is in

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