63
SETBACK OPERATION
With the real time clock in the PPC4000, scheduled setback operation can be implemented to allow
the system to operate to an alternate steam pressure or water temperature during off peak times. The
scheduled setback time applies to every day of the week. That is, there are not individual setback
times for each day of the week. Digital inputs are available that allow the user to override the setback
operation for a pre-determined time when in setback mode or to place the system in a forced setback
mode.
From the top layer menu, the user scrolls to SETBACK SETUP> and presses the NEXT key to
access this submenu.
For setback to work properly the user should ensure the real time clock has been properly set up. See
previous section titled REAL TIME CLOCK.
The sensor used option applies to sensor 1 and sensor 2. If no sensors are setup then USED cannot be
selected. Typically sensor 1 is the process control variable and in the case of a steam boiler could be
a common header sensor.
STBCK STEAM and STBCK WATER refer to the sensor selected and its configuration. Only sen-
sors selected can be shown. (If a sensor selected is made unused at a later time then all setback setup
information is cancelled or erased).
END STBCK
(End Setback Period): This setpoint determines at what time the PPC4000 changes
over from the setback setpoint to the normal setpoint (SETPOINT 1 or SETPOINT 2).
BGN STBCK
(Begin Setback Period): This setpoint determines at what time the PPC4000 starts the
setback schedule.
STBCK SUN
(Daily Setback Options): This selects the options for operating in the setback mode
for Sunday. These options are:
•
ALL STBCK
(All Setback). The PPC40000 controls the boiler at the setback setpoint for the
entire day (24 hours).
•
NO STBCK
(No Setback). The PPC4000 DOES NOT setback the boiler for this day, but
controls the boiler at the normal setpoint for the entire day (24 hours).
•
SCHEDULE
(Scheduled Setback) The PPC4000 controls the boiler according to the Set-
back Schedule for the time specified in END STBCK and BEGIN SETBCK.
Assured Low Fire Cutoff
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