York YCAL0080SC manual Evaporator Pump Start Contacts, System Run Contacts, Alarm Status Contacts

EVAPORATOR PUMP START CONTACTS

Terminal block CTB2 - terminals 23 to 24, are normally open contacts that can be used to switch field supplied power to provide a start signal to the evaporator pump contactor. The contacts will be closed when any of the following conditions occur:

1.Low Leaving Chilled Liquid Fault

2.Any compressor is running.

3.Daily schedule is not programmed OFF and the Unit Switch is ON.

The pump will not run if the micropanel has been pow- ered up for less than 30 seconds, or if the pump has run in the last 30 seconds, to prevent pump motor over- heating. Refer to figure 5 and unit wiring diagram.

SYSTEM RUN CONTACTS

Contacts are available to monitor system status. Normally-open auxiliary contacts from each compressor contactor are wired in parallel with CTB2 - terminals 25 to 26 for system 1, and CTB2 - terminals 27 to 28 for system 2 (YCAL0040 - YCAL0080). Refer to Figure 5 and unit wiring diagram.

ALARM STATUS CONTACTS

Normally-open contacts are available for each refrigerant system. These normally-open contacts close when the system if functionally normally. The respective contacts will open when the unit is shut down on a unit fault, or locked out on a system fault. Field connections are at CTB2 terminals 29 to 30 (system 1), and terminals 31 to 32 (system 2 YCAL0040 - YCAL0080).

REMOTE START/STOP CONTACTS

To remotely start and stop the chiller, dry contacts can be wired in series with the flow switch and CTB1 - termi- nals 13 to 14. Refer to Figure 5 and unit wiring diagram.

FORM 150.62-NM1

REMOTE EMERGENCY CUTOFF

Immediate shutdown of the chiller can be accomplished by opening a field installed dry contact to break the elec- trical circuit between terminals 5 to L on terminal block CTB2. The unit is shipped with a factory jumper installed between terminals 5 to L, which must be removed if emergency shutdown contacts are installed. Refer to Figure 5 and unit wiring diagram.

PWM INPUT

The PWM input allows reset of the chilled liquid set- point by supplying a “timed” contact closure. Field wir- ing should be connected to CTB1 - terminals 13 to 20. A detailed explanation is provided in the Unit Control section. Refer to Figure 5 and unit wiring diagram.

LOAD LIMIT INPUT

Load limiting is a feature that prevents the unit from loading beyond a desired value. The unit can be “load limited” either 33%, 50%, or 66%, depending on the number of compressors on unit. The field connections are wired to CTB1 - terminals 13 to 21, and work in conjunction with the PWM inputs. A detailed explana- tion is provided in the Unit Control section. Refer to fig- ure 5 and unit wiring diagram.

When using the Load Limit feature, the PWM feature will not function -

SIMULTANEOUS OPERATION OF LOAD LIMITING AND TEM- PERATURE RESET (PWM INPUT) CANNOT BE DONE.

FLOW SWITCH INPUT

The flow switch is field wired to CTB1 terminals 13 - 14. See Figure 5 and unit wiring diagram.

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YORK INTERNATIONAL 13