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Siemens Building Technologies
Basic Documentation RVP540 / RVP550
CE1P2488en
HVAC Products
Description of the heating engineer settings
18.10.2002
4.203 Switching differential of the room
temperature (SDR)
•
Temperature control with pump heating circuit
•
Prevents overtemperature in the room in the case of pump heating circuits
Serves as a room temperature limitation with pump heating circuits
Setting range
Unit
Factory setting
– – . – / 0.5...4
K
0.0
The switching differential for two-position control will be changed.
Entry:
- - . -
Switching differential is inactive
•
The pump always remains activated
Decrease:
Switching differential will become smaller
•
Pumps are switched on and off
more often
•
Room temperature varies within a
narrower
band
Increase:
Switching differential will become greater
•
Pumps are switched on and off
less often
•
Room temperature varies within a
wider
band
With pump heating circuits, the amount of heat supplied must be controlled by switch-
ing the pumps on and off. This is accomplished with 2-position control by means of the
room temperature's switching differential.
Room temperature acquisition requires a room unit.
Pump ON
TRx =
TRw
Pump OFF
TRx =
TRw + SDR
Benefit
Description
Setting
Effect
Room temperature
control
Note
Functioning:
OFF
ON
P
°C
TRx
TRw+SDR
23
71
D
02
TRw
t
Switching differential
Legend
TRx Actual value of the room
temperature
TRw Room temperature setpoint
SDR Switching differential of the
room
temperature
ON Switch-on
point
OFF Switch-off
point
t Time
P Pump