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Siemens Building Technologies
Basic Documentation RVD230
CE1P2383en
HVAC Products
12 Function block Space heating
27.05.2004
12.9.8 Maximum
rate
of
flow temperature increase
t
t
252
2D07
T
Vw
T
Vw
Maximum rise: =
∆
TVw
–––––––
∆
t
t Time
∆
t
Unit of time
TVw Flow temperature setpoint
∆
TVw Rate of setpoint increase per unit of time
The rate of increase of the flow temperature setpoint can be limited to a maximum. In
that case, the maximum rate of increase of the flow temperature setpoint is the selected
temperature per unit of time (°C per hour). This function
•
prevents cracking noises in the piping
•
protects objects and construction materials that are sensitive to quick temperature
increases (e.g. antiquities)
•
prevents excessive loads on heat generating equipment
The limit value is to be set on operating line 77.
This function can be deactivated (setting ---).
Limitation of the rate of increase does not act on the primary controller and the d.h.w.
circuits.
12.10 Frost protection for the building
12.10.1 General
Frost protection for the house or building makes certain that the room temperature will
not fall below a certain level. If the room temperature falls below the setpoint for frost
protection, the controller will maintain a room temperature equivalent to that setpoint
plus the switching differential of 1 K.
For this purpose, both the controller and the heat source must be ready to operate
(mains voltage present).
The setpoint for frost protection is to be set on the end-user level, operating line 3.
This function cannot be deactivated.
Plant types 0–x do not feature frost protection for the building; they only provide d.h.w.
heating.
12.10.2 Mode of operation with room sensor
The controller compares the room temperature with the adjusted setpoint for frost pro-
tection. If the room temperature falls below that setpoint, the controller will activate the
heating circuit pump to maintain the flow temperature at that setpoint plus the switching
differential of 1 K.
With the room temperature sensor, frost protection for the building has priority over the
ECO function.
Function
Effect on d.h.w. heating
