© 2010 D 265 - 07/10
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Section E1: Setpoint
Note:
Setpoint operation is only available when DHW MODE is set to OFF.
SETPOINT
The control can operate to satisfy the requirements of a setpoint load in addition to a space heating load. A setpoint load overrides
the current outdoor reset temperature and WWSD setting in order to provide heat to the setpoint load.
SETPOINT DEMAND
A Setpoint Demand is required in order for the control to provide heat to the setpoint load.
The control registers a setpoint demand when a voltage between 24 and 230 V (ac) is
applied across the
Setp
/
DHW Dem
and
Com Dem
terminals (31 and 30). Once voltage
is applied, the Setpoint Demand pointer turns on in the LCD. The control operates the
boiler(s) to maintain at least the setpoint setting.
BOILER TARGET DURING SETPOINT
The boiler target temperature during a setpoint demand is increased to at least the Setpoint
setting. This temperature is maintained as long as the control has a setpoint demand.
SETPOINT MODE
SETP MODE 1 - Setpoint in Parallel
Whenever a setpoint demand is present, the boiler(s) is operated to maintain the setpoint target. The primary pump contact does not
close, but may operate based on a Boiler Demand or on an external input system.
It is assumed that the Setpoint pump will provide adequate flow through the heat exchanger and the boiler.
SETP MODE 2 - Setpoint in Parallel with Priority
Whenever a setpoint demand is present, the boiler(s) is operated to
maintain the setpoint target and the primary pump
(Prim P1
) contact
is opened.
It is assumed that the Setpoint pump will provide adequate flow
through the heat exchanger and the boiler.
SETP MODE 3 – Primary Pump during Setpoint
Whenever a setpoint demand is present, the primary pump
(Prim P1
) is turned on and the boiler(s) is operated to maintain the
setpoint target.
SETPOINT PRIORITY OVERRIDE
The setpoint has a Priority Override while in SETP MODE 2. In order to prevent the building from cooling off too much or the
possibility of a potential freeze up during setpoint priority, the control limits the amount of time for setpoint priority. The length of
Setpoint priority is determined by the Priority Override setting. Once the allowed time for priority has elapsed, the control overrides
the setpoint priority and operates setpoint and heating simultaneously by turning on the primary pump
(Prim P1
).
CONDITIONAL SETPOINT PRIORITY
If the boiler(s) supply temperature is maintained at or above the required temperature during setpoint generation, this indicates that
the boiler(s) has enough capacity for setpoint and possibly heating as well. As long as the boiler target temperature is maintained
and the heating and setpoint targets are similar, setpoint and heating occur at the same time.
30
Com
Dem
31
Setp/
Dem
24 to 230 V (ac)
Setpoint Device
Boiler
Pumps
Primary
Pump
Section E1
Setpoint
Section E: Setpoint Operation
