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Siemens Building Technologies
Basic Dokumentation RVA63.280, RVA53.280
CE1P2374E
Landis & Staefa Division
19.04.2001
2.25
Switching differential of room temperature
(SDR)
Temperature control with pump heating circuits.
Prevents overtemperatures in the rooms in the case of a pump heating circuit.
Serves as a room temperature limitation with pump heating circuits
Setting range
Unit
Factory setting
– . – / 0.5...4.0
°C
– . –
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
The room temperature sensor must be active
•
This function only acts in automatic mode
•
The display will show "ECO“
With pump heating circuits, the amount of heat supplied is controlled by switching the
pumps on and off. This is accomplished with 2-position control by means of the room
temperature's switching differential.
Functioning:
OFF
ON
P
°C
TRx
TRw+SDR
2371
D
0
2
TRw
t
Legend
TRx
Actual value of the room
temperature
TRw
Room temperature setpoint
SDR
Switching differential of
room temperature
P
Pump
ON
Switch-on point
OFF
Switch-off point
t
Time
Pump ON
TRw
Pump OFF
TRw =TRw + SDR
°C
23
73
Z
1
4
ON
OFF
w
TRx
Actual value of room
temperature
TRw
Room temperature setpoint
SDR
Switching differential of
room temperature
w
Setpoint
102
Switching differential of
room temperature
Switch-on point
Switch-off point
Benefits
Description
Setting
Effect
Note
Room temperature
control
Switching differential