Setpoints Screen; Figure 29 - Setpoints Screen - York YD Series Operation Manual

SECTION 2 – OPTIVIEW CONTROL CENTER
Overview
This screen provides a convenient location for pro-
gramming the most common setpoints involved in the
chiller control. This screen also serves as a gateway to
a sub-screen for defining the setup of general system
parameters.
Display Only
Leaving Chilled Liquid Temperature - Setpoint
Displays the present setpoint to which the chiller is
operating whether controlled remotely or locally. This
value could come from a 0-20 mA, 4-20 mA, 0-10VDC
or 2-10VDC input in Analog Remote mode, PWM sig-
nal in Digital Remote mode, MicroGateway interface
in ISN mode, or a locally programmed value.
Leaving Chilled Liquid Temperature Cycling -
Shutdown
Displays the Leaving Chilled Liquid Temperature at
which the chiller will shut down to avoid over-cool-
ing the building. This value is calculated by subtract-
ing the Leaving Chilled Liquid Temperature Cycling
Offset – Shutdown from the Leaving Chilled Liquid
Temperature – Setpoint. If this value is below the abso-
lute minimum allowed shutdown temperature the mini-
mum value is displayed.

FIGURE 29 - SETPOINTS SCREEN

86

SETPOINTS SCREEN

Leaving Chilled Liquid Temperature Cycling – Re-
start
Displays the Leaving Chilled Liquid Temperature at
which the chiller will restart after it has shut down due
to over-cooling temperature. This value is calculated
by adding the Leaving Chilled Liquid Temperature
Cycling Offset – Restart to the Leaving Chilled Liquid
Temperature – Setpoint.
Chiller Current Limit Setpoint
Displays the current limit that is in effect during the
Chiller Steady State period (this period is in effect af-
ter the Chiller Pulldown Period is no longer in effect).
The Chiller Current Limit Setpoint could be from a
0-20mA, 4-20mA, 0-10Vdc or 2-10Vdc input in Ana-
log remote mode or PWM input in Digital remote mode
or Microgateway interface in ISN remote mode or a
Local Chiller Limit Setpoint entered at the Keypad.
The Chiller Pulldown Period is in effect from the in-
stant the chiller enters "System Run" until the Leaving
Chilled Liquid Temperature is within 2ºF of the Leav-
ing Chilled Liquid Temperature Setpoint. During this
period, the Chiller Pulldown Demand Limit Setpoint is
in effect. The Chiller Current Limit Setpoint is in effect
for the remainder of "System Run". Refer to detailed
explanation of the Chiller Current Limit Setpoint in
the Electro-mechanical Starter Screen section.
FORM 160.69-O1
ISSUE DATE: 9/30/2012
LD08625
JOHNSON CONTROLS