Johnson Controls YORK YVAM 0350, Operation & Maintenance Manual

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prompt described previously. It allows the user to log on at a higher access level without returning
to the Home screen. After logging on, the user can then modify setpoints on that screen.
Programming setpoints
About this task:
The control center uses the setpoint values to control the chiller and other devices that are
connected to the chiller system. Setpoints can fall into several categories. They could be numeric
values, such as 45.0°F for the Leaving Chilled Liquid Temperature, or they could enable or disable
a feature or function. Regardless of which setpoint is being programmed, use the following
procedure:
1. Press the setpoint button. A dialog box appears displaying the present value, the upper and
lower limits of the programmable range, and the default value.
2. If the dialog box begins with the word
ENTER
, use the numeric keys to enter the required
value. Leading zeroes are not necessary. If a decimal point is necessary, press the decimal (•)
button, for example, 45.0.
To set the entry value to the default for that setpoint, press the ▲ button. To clear the
present entry, press the ▼ button. The ◄ button is a backspace key and causes the entry
point to move back one space. If the dialog box begins with
SELECT
, use the ◄ and ►
buttons to select the preferred value.
If the previously defined setpoint is required, press the X (Cancel) button to dismiss the
dialog box.
3. Press the Enter ( ✓ ) button.
If the value is within range, it is accepted and the dialog box disappears. The chiller begins to
operate based on the new programmed value. If out of range, the value is not accepted and
the user is prompted to try again.
Manual controls
Some buttons are used to perform manual control functions. These may involve manual control
of items such as the compressor speed or valve actuators. These are mostly restricted to qualified
technicians in Service access. Other buttons in this category are used to initiate and terminate
processes such as calibrations or reports.
Free cursor
On screens that contain many setpoints, a specific button might not be assigned to each setpoint
value. A soft key is assigned to enable the cursor arrow buttons below the numeric keypad, which
are used to highlight the setpoint field. At this point, the Enter ( ✓ ) button is pressed to bring up a
dialog, which prompts the user to enter a new setpoint value. The X button cancels cursor mode.
See the Schedule screen for an example.
Navigation
To maximize the amount of values that the panel can display to the user, and in order to place
those values in context, multiple screens have been designed to describe the chiller operation. In
order to move from one screen to the next, navigation buttons have been defined. These buttons
allow the user to either move forward to a subscreen of the present screen, or move backward
to the previous screen. Except for the Home screen display, the upper-right soft button always
returns the user to the Home screen. Navigating is as simple as pressing the button next to the
label containing the name of the preferred screen. The system immediately refreshes the display
with the graphics for that screen. The following figure is a layout of all the screens and how they are
connected.
31 YVAM Control Center