York YCAL0014SC, YCAL0080SC manual Unit Controls, Field And Factory Electrical Connections

Unit Controls

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035-15961-000

035-15961-000

LD03875

FIG. 7 – FIELD AND FACTORY ELECTRICAL CONNECTIONS

OPTIONAL REMOTE TEMPERATURE RESET BOARD

If a 4-20mA signal is available, it is applied to termi- nals A+ and A- and jumpers are applied to JU5 and JU3 on the reset board. The mA signal is conditioned to a 1-11 second PWM output. The PWM output is then supplied to the PWM input on the microboard at CTB 1 terminals 13 - 20. To calculate the chilled liquid setpoint for values between 4mA and 20 ma use the following formula:

setpoint = local chilled liquid setpoint + °reset

°reset = (mA signal - 4) x (*Max Reset Value) 16

Example:

Local Chilled Liquid Setpoint = 45° (7.22°C)

*Max Reset Value = 10°F (5.56°C)

Input Signal = 12 mA

(English)

°reset = 8mA x 10°F = 5°F reset 16

setpoint = 45°F + 5°F = 50°F

(Metric)

°reset = 8mA x 5.56°C = 2.78°C reset 16

setpoint = 7.22°C + 2.78°C = 10.0°C

A 240-24 Volt Ratio Transformer (T3) is used to derive nominal 12 volt out- put from the 120 volt supply.

If the Contact Closure input is used. The connections are made to terminals C and D and only jumper JUI must be in place on the reset board. This input is used when a single reset value is needed. When the contacts are closed, the remote temperature reset board will con- vert this contact closure to a PWM signal that is applied to CTB 1 terminals 13 - 20.

To set the PWM output, the contacts must be closed on inputs C - D, and potentiometer R11 (located on the front edge of the PC board) is adjusted to 10VDC as mea- sured at TP3 to terminal 10 on the circuit board. The reset value will be the “Max EMS-PWM Remote Temp. Reset” setpoint value programmed in the SETPOINTS section under the Cooling Setpoints key.

NOTE: The coil of any added relay used for reset must be suppressed to prevent possible component damage. Use YORK PN031-00808-000 suppressor.

*Max Reset Value is the “Max EMS-PWM Remote Temp. Reset” setpoint value described in the programming section under Cooling Setpoints. Programmable values are from 2°F to 40°F (1.11°C to 11.11°C).

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