Johnson Controls YORK OPTIVIEW CONTROL CENTER, Operation Manual

Page: 65 / 142

JOHNSON CONTROLS
65
SECTION 2 - OPTIVIEW OPERATION
FORM 160.10-O1
ISSUE DATE: 4/27/2018
2
due to over-cooling. This value is calculated by adding
the Leaving Chilled Liquid Temperature Cycling Off-
set Restart to the Leaving Chilled Liquid Temperature
Setpoint.
Leaving Chilled Liquid Temperature Cycling –
Restart Offset
Displays the programmed number of degrees the
chilled liquid is permitted to reach above the leaving
chilled liquid temperature setpoint before the chiller
will restart.
Current Limit Setpoint
Displays the active current limit setpoint, as a percent-
age of full load amps. In local mode, this is the local-
ly programmed current limit setpoint. In ISN remote
mode, this is the setpoint received from the Micro-
Gateway interface. In analog remote mode, this is the
setpoint received via 0-10VDC, 2-10VDC, 0-20mA or
4-20mA input. In digital remote mode, this is a Pulse
Width Modulation (PWM) signal input.
PROGRAMMABLE
Local Leaving Chilled Liquid Temperature –
Setpoint
Access Level Required: OPERATOR
This value allows the user to define the leaving chilled
liquid temperature that is to be maintained by the chill-
er. The temperature is programmable over the range of
38.0°F to 70.0°F (water) or 10.0°F to 70.0°F (brine).
The range is 36.0°F to 70.0°F (water) if Smart Freeze
is enabled.
Local Leaving Chilled Liquid Temperature –
Range
Access Level Required: OPERATOR
This is the range that a remote device is able to adjust
the leaving chilled liquid temperature setpoint above
the temperature set locally at the OptiView. The range
setpoint is programmable to either 10.0°F or 20.0°F,
with a default of 20.0°F. This setpoint value is added to
the local leaving chilled liquid temperature (see above)
value to create a range limit over which a remote de-
vice can adjust the setpoint.
• For example, if the range is programmed for 10°F
and the locally programmed value of the chilled
liquid temperature is 45°F, then the remote device
is able to change and set the leaving chilled liquid
temperature setpoint over the range 45.0° - 55.0°F.
A remote device that provides an analog signal (0-
20mA, 4-20mA, 0-10VDC or 2-10VDC) in analog re-
mote mode or a PWM signal in digital remote mode
defines the setpoint change as an offset value.
• For example, if the setpoint is 45.0°F and the de-
sired setpoint is 50.0°F, then 5.0°F would be the
input on the remote device.
A MicroGateway (in ISN Remote mode) can define the
setpoint through a serial data stream. In this case, the
incoming setpoint is not an offset that is applied to the
leaving chilled liquid temperature setpoint value, but is
the actual setpoint value.
Leaving Chilled Liquid Temperature Cycling
Offset – Restart
Access Level Required: OPERATOR
This value specifies the number of degrees above the
leaving chilled liquid temperature setpoint the liquid is
permitted to reach before the chiller will restart after a
“LEAVING CHILLED LIQUID – LOW TEMPERA-
TURE” cycling shutdown. The value is programmable
over a range of 0.0°F to 70.0°F (dependant on setpoint
temperature) above the chilled liquid setpoint, to a
maximum restart value of 80.0°F. The chiller will au-
tomatically restart when this temperature is reached.
This setpoint can be used to reduce chiller cycling by
delaying the chiller restart until the cooling load has
increased.
Leaving Chilled Liquid Temperature Cycling
Offset – Shutdown
Access Level Required: OPERATOR
This value specifies the number of degrees below the
leaving chilled liquid temperature setpoint the chilled
liquid can reach before the OptiView performs a
“LEAVING CHILLED LIQUID – LOW TEMPERA-
TURE” cycling shutdown. This setpoint is program-
mable over a range of 1.0°F to 64.0°F (dependant on
setpoint temperature), to a minimum cutout of 36.0°F
(water), 34.0°F (water with Smart Freeze enabled) or
6.0°F (brine). This prevents over-cooling of the chilled
liquid.
Anytime the leaving chilled liquid temperature setpoint