York YCAL0014SC, YCAL0080SC manual Unit Controls, PROGRAM key

Unit Controls

PROGRAM key

There are six operating parameters under the PRO- GRAM key that are programmable. These setpoints can be changed by pressing the PROGRAM key, and then the ENTER/ADV key to enter Program Mode. Continu- ing to press the ENTER/ADV key will display each op- erating parameter. While a particular parameter is be- ing displayed, the UP and DOWN arrow keys can be used to change the value. After the value is changed, the ENTER/ADV key must be pressed to enter the data into memory. Table 29 shows the programmable limits and default values for each operating parameter.

Following are the displays for the programmable val- ues in the order they appear:

@ D I S C H A R G E P R E S S U R E

C U T O U T = 3 9 5 P S I G

DISCHARGE PRESSURE CUTOUT is the discharge pressure at which the system will shutdown as moni- tored by the optional discharge transducer. This is a software shutdown that acts as a backup for the me- chanical high pressure switch located in the refrigerant circuit. The system can restart when the discharge pres- sure drops 40 PSIG (2.76 BARG) below the cutout point.

If the optional discharge pressure transducer is not in- stalled, this programmable safety would not apply. It should be noted that every system has a mechanical high pressure cutout that protects against excessive high discharge pressure regardless of whether or not the op- tional discharge pressure is installed.

S U C T I O N P R E S S U R E

C U T O U T = 4 4 . 0 P S I G

The SUCTION PRESSURE CUTOUT protects the chiller from an evaporator freeze-up. If the suction pres- sure drops below the cutout point, the system will shut down.

There are some exceptions when the suction pressure is permitted to tem- porarily drop below the cutout point. Details are explained under the topic of System Safeties.

L O W A M B I E N T T E M P

C U T O U T = 2 5 . 0 ° F

The LOW AMBIENT TEMP CUTOUT allows the user to select the chiller outside ambient temperature cutout point. If the ambient falls below this point, the chiller will shut down. Restart can occur when temperature rises 2°F (1.11°C) above the cutout setpoint.

L E A V I N G L I Q U I D T E M P

C U T O U T = 3 6 . 0 ° F

The LEAVING LIQUID TEMP CUTOUT protects the chiller from an evaporator freeze-up. Anytime the leav- ing chilled liquid temperature drops to the cutout point, the chiller shuts down. Restart will be permitted when the leaving chilled liquid temperature rises 2°F (1.11°C) above the cutout setpoint.

When water cooling mode is programmed (Options key), the value is fixed at 36.0°F (2.22°C) and cannot be changed. Glycol cooling mode can be programmed to values listed in Table 28.

A N T I R E C Y C L E	T I M E
= 6 0 0 S E C

The anti-recycle timer message shows the amount of time left on the respective systems anti-recycle timer. The programmed ANTI RECYCLE TIME will start to count down at the start of the systems number one com- pressor. In effect, this is the minimum time start-to-start on the respective systems number one compressor.

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