Siemens RVL481 - Deflection

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Siemens Heating and D.h.w. Controller RVL481 CE1P2541en
Building Technologies 10 Function block "Space heating" 20.05.2008
2540Z09
The setting is to be made on operating lines 14 and 15.
Operating line Setpoint
14 TV1, current flow temperature setpoint at an outside tempera-
ture of 15 °C
15 TV2, current flow temperature setpoint at an outside tempera-
ture of –5 °C
The type of setting is to be entered on operating line 73.
Operating
line 73
Bar Operating line 14 Operating line 15
0 Acting No action No action
1 No action Acting Acting
2 No action Display function only,
adjustment only via LPB
Display function only,
adjustment only via LPB
10.6.3 Deflection
The heat losses of a building are proportional to the difference between room tempera-
ture and outside temperature. By contrast, the heat output of radiators does not in-
crease proportionally when the difference between radiator and room temperature
increases. For this reason, the radiators' heat exchanger characteristic is deflected. The
heating curve's deflection takes these characteristics into consideration.
In the range of small slopes (e.g. with underfloor heating systems), the heating curve is
practically linear – due to the small flow temperature range – and therefore corresponds
to the characteristic of low temperature heating systems.
The slope ”s” is determined according to the following formula:
s =
T
Vw(-5)
- T
Vw(+15)
20 K
s Heating curve slope
T
Vw(−5)
Flow temperature setpoint at an outside temperature of −5 °C
T
Vw(+15)
Flow temperature setpoint at an outside temperature of +15 °C
On the controller, the heating curve is shown as a straight line. This straight line corre-
sponds exactly to the deflected heating curve, because the non-linear outside tempera-
ture scale corresponds to the deflection.
The heating curve is valid for a room temperature setpoint of 20 °C.
Setting with the bar
Setting on the operating
lines
Selection of setting