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Siemens Building Technologies
Basic Documentation RVD230
CE1P2383en
HVAC Products
13 Precontrol
27.05.2004
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 x–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.
13.6 Frost
protection
Frost protection for the plant prevents the precontrolled flow from freezing up by making
use of the system pump.
All zone controllers connected to the precontrolled flow take care of the frost protection
in their zones. The assigned heat demand is communicated to the primary controller via
LPB.
13.7 Other
functions
The primary controller does not consider the following functions or has them deacti-
vated:
•
Room temperature setpoint adjustments
•
Heating program
•
Outside temperature-dependent functions (heating curve, etc.)
•
Quick setback
•
Optimization
•
Room functions ( limitation, heat gains, etc.)
•
Automatic ECO function
For the heating circuit only, the following functions remain active with plant type 7–2:
•
All heating circuit functions including the heating program
•
Entry of holiday data
By contrast, the following functions will be maintained:
•
Maximum limitation of the primary return temperature
•
Maximum limitation of the temperature differential
Heat demand consumers
Setpoint consumer
Forced signal heat converter
Flow setpoint heat converter
Pump consumer
Heat demand heat converter