York YK-EP Operation And Maintenance Manual page 37

Table 19: Display only fields
Field/LED name
Head Pressure Setpoint
Control Valve Command
Control Valve Control Mode
Table 20: Programmable
Button
Head Pressure Setpoint
Minimum Position
Shutdown Position
Control Valve Output
Settings – Type
Control Valve Output
Settings – Direction
Control Valve Output
Settings – Set
Control Valve Output
Settings – Auto
Change Setpoints
YK-EP Style B Centrifugal Chiller
Description
Displays the active Head Pressure Setpoint to which the head
pressure is being controlled.
Displays the position command being sent to the Control Valve.
Displayed over the range of 0.0% to 100%. The actual value of the
output signal for a given error depends on whether the PID OUTPUT
Setpoint is set to direct or reverse. If set to direct, the 0.0% output
will be at minimum; the 100% output will be at maximum. If set to
reverse, the 0.0% output will be at maximum; the 100% output will
be at minimum.
Displays whether the Control Valve is in automatic or manual
control.
Description
(15.0 to 60 PSID; default 23.0 PSID) Sets the pressure differential to
which the Control Valve will control the Head Pressure.
(0 to 100%; default 0%) Sets the minimum position that the valve can
drive to while the chiller is running.
(0 to 100%; default 0%) Sets the position that the valve will drive to
while the chiller is off.
(0-10v or 4 to 20mA; default 0-10v) Sets the output signal to the
Control Valve to be in the form of either 0 to 10VDC or 4 to 20mA.
(Direct or Reverse) Allows the output signal to the Control Valve to
be set to direct or reverse acting. When set to direct, the voltage or
current signal to the Control Valve is at minimum for a 0% command
and at maximum for a 100% command. When set to reverse, the
voltage or current signal to the Control Valve is at maximum for a
0% command and at minimum for a 100% command.
(0.0% to 100%; default 0.0%) Allows the Control Valve to be manually
set to a position between 0.0% and 100%.
Places the Control Valve in automatic control.
Use to enter the Head Pressure Control PID variables below.
Pressing this key places a green box around the first changeable
setpoint. Use the up/down, left/right arrows to place the selection
box around the desired setpoint. With the setpoint selected, press
the ENTER key. A dialog box appears with the range of settings.
Using the NUMERIC keys, enter desired value. Then, press the
ENTER key.
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