Direct Digital Controller
128 Direct Digital Controller fw 4.013 – Ed. 01/2013
Figure 25 – EXAMPLE OF INITIAL SCREEN FOR CONTROLLING TWO-LINE COOLING/HEATING PLANTS
To access the “Heating/Cooling Plant Control” menu select from the initial screen.
The figure on the right shows the “Plant control” menu screen and the
relative buttons/commands described below.
Main ON/OFF switch. Turn the knob to position the cursor on the button and press the same to
activate it (symbol of the ON/OFF button in the ON position
). In case of Multi-DDC plant, it
is ON only on the Master DDC; on the Slave DDC(s) it reflects the ON/OFF status set on the Master.
Group ON/OFF switch. Button disabled (always ON) for plants managed by a single DDC. Turn
the knob to position the cursor on the button and press the same to activate it (symbol of the ON/OFF
button in the ON position ). If in the OFF position, it allows all the machines managed by the
specific DDC to be switched off.
Button for enabling/disabling General water T timer. To disable the General water T timer, i.e. not
use general timer programming (relative on/off command always ON and default setpoint in
use), position the cursor on the button and press the knob (General water T timer command
symbol
not active). WARNING: DISABLING THE GENERAL WATER T TIMER ENTAILS
AUTOMATICALLY DISABLING THE PARTIAL WATER T TIMER (
).
Button for enabling/disabling Partial water T timer (disabled for plants managed by a single DDC). If
enabled, the specific DDC uses also the partial timer programming (see Paragraph
3.4.1.1.1.4
– “Partial water T
timer”);
Chronothermostat button disabled (on/off command not enabled in MAN operating mode).
COOLING/HEATING switching button - two-line hot/cold plants only (
COOLING,
HEATING).
If the plant is ON, cooling/heating switching or vice versa lasts 10 minutes.
If the plant is OFF (for more than 10 minutes), cooling/heating switching is instantaneous.
KEY:
A Symbol indicating operating mode (cooling/heating)
B System identification number
C System ON/OFF status
D Setpoint set for water temperature (if the plant is ON)
E Button for accessing “Plant control” menu
F System inlet and outlet water temperature
G Symbol indicating system type (cooling/heating)
H System inlet water temperature.
I It permits to display the operating parameters of the sanitary
hot water plant (
)
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