Basic Documentation

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Siemens Modular Heating Controller RMH760B CE1P3133en
Building Technologies 5 General functions, fundamentals 2017-09-29
The change from pump A to pump B is made after a certain pause, e.g. to prevent
surge voltages or excessive water pressures:
3131D44
A
B
Depending on the changeover priority, the pump kick will act as follows:
Operating state of the
pumps
Impact of pump kick
With automatic changeover
With fixed assignment
Both pumps do not run
(summer operation)
Kick first acts on the pump that
was in operation last
Kick first acts on the
reserve pump and then on
the working pump
One of the 2 pumps
runs
Not applicable Kick only acts on the
reserve pump
The changeover delay also acts with pump kicks.
5.8.2 Overload message and supervision of flow
As with every digital input, the normal position can also be parameterized for the pump
fault inputs and the flow input (… > Settings > Inputs > RM… (controller or module type) >
Normal position).
If a twin pump is installed, changeover to the other pump takes place in the event of
fault. In any case, a fault status message will be delivered.
For acknowledgement, following applies:
• A fault due to a missing fault status message must be acknowledged and reset
• If there is a pump fault, the respective function block will be stopped
For faults due to overload, the acknowledgement and reset behavior can be
parameterized.
In the case of twin pumps, the fault behavior of the respective function block becomes
active only should both pumps fail.
Flow supervision only becomes active 60 seconds after the pump is switched on.
Number Text Description
2526
[Heat circuit 1 pump]
overload
Heating circuit pump of heating circuit 1
overloaded
2527
[Heat circuit 1 pump B]
overload
Heating circuit pump B of heating circuit 1
overloaded
2528
[Heat circuit 1 pump] no flow
Heating circuit pump of heating circuit 1 with
faulty flow
2529
[Heat circuit 1 pump B] no
flow
Heating circuit pump B of heating circuit 1
with faulty flow
2530
[Heat circuit 1 pump] fault
Heating circuit pump(s) of heating circuit 1
faulty; partial plant stop
For the complete list of fault status messages, refer to section 16.1 " List of fault
numbers".
Changeover with
positive delay
Pump kick
Fault status messages
using the example of a
heating circuit twin pump