Siemens RVD240 - Page 53

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Siemens Building Technologies Basic documentation RVD240 CE1P2384en
HVAC Products 12 Function block Space heating 27.05.2004
• If there is no forced signal, the consumers / heat converters perform normal pump
overrun in agreement with the set overrun time (also refer to sections 12.7 for the
heating circuit pump and 15.7 for the d.h.w. pump)
• If a forced signal is received, the loads continue to draw heat from the heat source in
the following manner:
− In mixing circuits, the previous setpoint is maintained; during overrun, that setpoint
appears on the display
− In pump circuits, the pump continues to run. If, at the same time, an internal pump
overrun is called for, a maximum selection of the 2 overrun times is made; in that
case, the longer overrun time applies
ON
OFF
0
t
t
72
0
ON
OFF
ON
OFF
ON
OFF
w
w
Y
ON Activation
OFF Deactivation
t Time
t
72
Overrun time (operating line 72)
w Setpoint
Y Manipulated variable
Plant types 1–4 and 4–4 do not respond to forced signals since heat is drawn from the
heat source only when d.h.w. is consumed.
If there is no forced signal, the loads and heat converters that have responded to the
forced signal react as follows:
• They close their mixing valves
• Their pumps continue to run for the set overrun time and then stop
D.h.w. discharging protection has priority over the pump and mixing valve overrun.
Heat demand consumers
Setpoint consumer
Forced signal heat converter
Flow setpoint heat converter
Pump consumer
Heat demand heat converter