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Siemens Building Technologies
Basic Documentation RVP540 / RVP550
CE1P2488en
HVAC Products
General control processes
04.11.2009
6.4 Protection against discharging after d.h.w.
heating
•
Inadvertent discharging of the d.h.w. storage tank will be prevented
”Protection against discharging after d.h.w. heating” prevents inadvertent discharging of
the d.h.w. storage tank resulting from pump overrun. Together with ”Protection against
discharging during d.h.w. heating” (operating lines 752
EXP
and 753
EXP
), efficient protec-
tion against discharging is thus ensured.
The controller compares the storage tank temperature with the common flow tempera-
ture or, in certain situations, with the boiler temperature.
If the flow temperature (or the boiler temperature) is lower than the storage tank tem-
perature, pump overrun will be stopped prematurely.
6.5 Automatic 24-hour heating limit
•
Automatic
shutdown
of
heating.
•
Saving energy without sacrificing comfort
This is a fast-acting savings function since the heating is switched off when there is no
more demand for heat. Economical operation is thus ensured throughout the year since
manual switching off during intermediate seasons is no longer required.
−
The automatic 24-hour heating limit does not function in continuous operation
−
When the automatic 24-hour heating limit is active, the display shows ”ECO”.
6.5.1 Without room influence
If no room unit is connected, the room temperature setpoint will
not
be readjusted by
the room influence. In that case, the automatic 24-hour heating limit operates according
to the selected setpoint of
or
.
The temperature basis used for this function are the values of the composite outside
temperature and the current room temperature setpoint.
If the flow temperature setpoint falls below the room temperature setpoint plus a cor-
rection value, the heating will be switched off.
Heating OFF:
TVw
≤
TRw
+
2
S/10
If the flow temperature setpoint exceeds the room temperature setpoint plus a correc-
tion value, the heating will be switched on.
Heating’s switch-on point:
TVw
≥
TRw
+
4
S/10
TVw Flow
temperature
setpoint
TRw
Room temperature setpoint
S
Slope of the heating curve
Benefit
Description
Process
Benefit
Description
Notes
Introduction
Process
Switching off
Switching on
