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Siemens Building Technologies
Basic Documentation RVP540 / RVP550
CE1P2488en
HVAC Products
General control processes
04.11.2009
6
General control processes
The functions described below require no settings. They are performed automatically
but have an impact on the plant.
For the rectification of faults, planning and plant maintenance, it may therefore be very
advantageous to know about their impact on plant operation.
6.1 Generating the boiler temperature setpoint
•
Demand-dependent control of the burner
Depending on the demand for heat, the different heating circuits call for different flow
temperature setpoints that must be ensured by the boiler control. However, since boiler
temperature control can consider only one setpoint, a selection is made.
Generally, the demand for the highest setpoint required by a consumer (e.g. by a heat-
ing circuit) generates the current boiler temperature setpoint.
The setpoint requirements considered stem from both controller-internal setpoints
(heating circuit or input H1) and setpoints transmitted via LPB.
Auxiliary functions, such as setpoint boosts and the like, are included in the setpoints
actually demanded at the time.
A demand for d.h.w. has priority over all other setpoint requirements, which means that
the required d.h.w. setpoint will be maintained, even if it is lower than that called for by
a heating circuit.
The boiler temperature is maintained at the highest setpoint currently demanded - un-
less d.h.w. is required.
TKw
Boiler temperature setpoint
TVw1
Flow temperature setpoint of the controller-internal heating circuit (incl. setpoint boost if any)
TVw2
Flow temperature setpoint of a controller-external heating circuit (incl. setpoint boost if any)
Introduction
Benefit
Description
Process
Exception
Effect
20
10
0
-10
-20
23
71
D
0
9
-30
40
30
60
50
80
70
90
TK
TV
T
TV
TA
w
w1
w2
gem
20
°C
Example
