Overview Of Setpoint And Control Sensor Selection - Siemens RVS41.813 User Manual

Switching differential
return temperature

Overview of setpoint and control sensor selection

Storage
1)
dmd
No
No
No
No
No
No
No
No
Yes
Siemens Switzerland Ltd
HVAC Products
Required sensors:
To enable the controller to put the heat pump into operation without control of a buffer
or combi storage tank, at least the return temperature sensor (B71) and the relevant
source temperature sensor must be installed. In the case of air-to-water heat pumps,
the evaporator sensor (B84) is required also.
Line no. Operating line
2840 Switching diff return temp
If the return temperature exceeds the setpoint by half the switching differential, the heat
pump will be switched off; if it falls below the setpoint by half the switching differential,
the controller will put the heat pump into operation.
If the return temperature setpoint drops below 30 °C, the switching differential is
reduced in a way that the switch-on point approaches the setpoint. With a return
temperature setpoint of 20 °C, the switch-on point is identical with the return
temperature setpoint.
T
30°C
20°C
The calculation of the return temperature setpoint is explained on operating line 5810
("Differential HC at OT –10 °C").
The function is not active when heat compensation is switched on.
Various factors determine which sensor is used to control to which setpoint. The
following table provides an overview on plant configurations and the sensors used to
control to which setpoint. Requirement is always a valid heat demand to the heat pump.
Response in case of faults is not considered here and not all listed cases may
represent reasonable plant configurations.
5)
B21 B71 B10 BZ
5810
- - -
- - ok
- Ok -
- Ok ok = 0
> 0
ok - -
ok - ok
ok Ok - = 0
> 0
ok Ok ok = 0
> 0
- - -
User manual RVS61.843, RVS41.813
6 The settings in detail
OFF
OFF
2840
ON
TRLw
2840
ON
temperature
Ta
T
TRLw
Ta
Compressor K1/K2
Sensors Setpoint
Off (fault 138)
Off (fault 138)
B71 T
Rw
B71 T
Rw
Off (fault 138)
Off (fault 138)
B71 T
Rw
B71 T
Rw
3)
On
Switch-off point
Switch-on point
Switching differential return
Outside temperature
Temperature of heat pump return
Return temperature setpoint
Electric immersion heater
K25/K26
2)
SD Sensors Setpoint
Off
B10 T
Vw
±BZ/2 B71 T
Rw
±BZ/2 B71 T
Rw
B10 T
Vw
B21 T
Vw
B21 T
Vw
±BZ/2 B71 T
Rw
B21 T
Vw
±BZ/2 B71 T
Rw
B21 T
Vw
On
28. September 2009
2)
SD
1°K
±BZ/2
±BZ/2
1°K
1°K
1°K
±BZ/2
1°K
±BZ/2
1°K
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