Siemens RVA63.242 - 6 General Control Processes; Generation of the Boiler Temperature Setpoint

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Siemens Building Technologies Basic Documentation RVA63.242, RVA53.242 CE1P2373E
Landis & Staefa Division General control processes 26.03.2001
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 influence on plant operation.
6.1 Generation of the boiler temperature setpoint
Demand-dependent control of the burner.
Depending on the temperature situation, the various heating circuits call for different
flow temperature setpoints as demanded by boiler temperature 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
heating circuit) generates the current boiler temperature setpoint.
The setpoint requirements considered stem from both controller-internal setpoints 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 -
unless d.h.w. is required.
20 10 0 -10 -20
2371D09
-30
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30
60
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TK
TV
T
TV
TA
w
w1
w2
gem
20
°C
TKw Boiler temperature setpoint
TVw1 Flow temperature setpoint of heating circuit 1 (incl. setpoint boost if any)
TVw2 Flow temperature setpoint of heating circuit 2 (incl. setpoint boost if any)
Introduction
Benefit
Description
Process
Exception
Effect
Example