YORK INTERNATIONAL
108
FORM 150.62-NM7 (103)
FIG. 12 – FIELD AND FACTORY ELECTRICAL CONNECTIONS
OPTIONAL REMOTE TEMPERATURE RESET BOARD
If a 4-20mA signal is available, it is applied to ter mi nals
A+ and A- and jumpers are applied to JU5 and JU3 on
the reset board. The mA signal is con di tioned to a 1 - 11
second PWM output. The PWM output is then supplied
to the PWM input on the microboard at CTB1 terminals
13 - 20. To calculate the chilled liquid setpoint for values
between 4mA and 20 mA use the following for mu la:
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
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setpoint = 7.22°C + 2.78°C = 10.0°C
If the Contact Closure input is used. The connec tions
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 CTB1 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 pro grammed in the SETPOINTS
section under the Cooling Setpoints key.
The coil of any added relay used for re-
set must be suppressed to prevent pos-
sible component damage. Use YORK
PN031-00808-000 suppres sor.
LD03875
A 240-24 Volt Ratio Transformer (T3)
is used to de rive nom i nal 12 volt out put
from the 120 volt supply.
* Max Reset Value is the “Max EMS-PWM Remote Temp. Reset” setpoint value described in the program ming section under Cooling Set-
points. Programmable values are from 2°F to 40°F (1.11°C to 11.11°C).
Unit Controls
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