Siemens RVL471 - Secondary Return Temperature (B71); Measurement; Handling Faults; Flow Temperature (B3)

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Siemens Building Technologies Basic Documentation RVL471 CE1P2524E
HVAC Products 4 Acquisition of measured values 23.10.2002
• If there is a return temperature from a controller of the same segment available on the
data bus, it is used (only with plant type 1–x). No error message will be generated
since this is the normal state in interconnected plants
• However, if there is no return temperature available on the data bus, the return tem-
perature limitation functions will be deactivated and an error message generated
4.5 Secondary return temperature (B71)
4.5.1 Measurement
The secondary return temperature is acquired with a sensor having a sensing element
LG-Ni 1000
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6–x), together with the primary return temperature.
4.5.2 Handling faults
If there is a short-circuit or open-circuit in the measuring circuit, and if the controller
requires the return temperature, DRT limitation will be deactivated. An error message
will be generated
4.6 D.h.w. flow temperature (B3)
4.6.1 Measurement
The d.h.w. flow temperature is acquired with a sensor having a sensing element
LG-Ni 1000
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4.6.2 Handling faults
If there is a short-circuit or open-circuit in the measuring circuit, the d.h.w. will no longer
be heated. The charging pump is deactivated and the actuating device (slipper or seat
valve) is shut.
An error message will be generated.
4.7 D.h.w. storage tank temperature (B31, B32)
4.7.1 Measurement
The storage tank temperature can be acquired as follows:
• With one or 2 sensors having a sensing element LG-Ni 1000
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• With one or 2 thermostats
This means that there are 2 measuring circuits.
4.7.2 Handling faults
The controller's response to faults in the measuring circuits depends on the type of
d.h.w. demand (setting on operating line 126):
• One d.h.w. storage tank temperature sensor (operating line 126 = 0):
In the event of a short-circuit or open-circuit in one of the 2 measuring circuits, the
controller continues to work with the other measuring circuit, if possible. An error mes-
sage will not be generated.