Basic Documentation

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Siemens Modular Heating Controller RMH760B CE1P3133en
Building Technologies 5 General functions, fundamentals 2017-09-29
Main menu > Settings > Boiler > Twin pump
Operating line
Range
Factory setting
Run priority
Auto / Twin pump A / Twin pump B
Auto
Changeover period
–60…0…+60 s
0 s
5.8.1 Changeover logic
For pump changeover, there are 3 choices available:
• Automatic changeover once a week; should the working pump become faulty,
changeover to the second pump will take place.
When switching on the next time, the pump that starts is always the pump that was in
operation last
• Twin pump A is always the working pump.
In the event of fault, changeover to pump B will take place. After correction of the
fault, a change back to pump A will be made
• Twin pump B is always the working pump.
In the event of fault, changeover to pump A will take place. After correction of the
fault, a change back to pump B will be made
The changeover time used is the same time as that used for the pump / mixing valve
kick (kick day and kick time).
Main menu > Commissioning > Settings > … or
Main menu > Settings > Protective functions
Operating line
Range
Factory setting
Kick day
Monday…Sunday
Monday
Kick time
00:00…23:59
10:00
Automatic changeover takes place after 168 hours (7 days) or – after a new start of the
plant – when kick day and kick time are reached.
Kick day and kick time for pump changeover remain valid even if the pump kick has
been deactivated.
The change from one pump to the other can take place as follows, depending on the
application:
• With no interruption
• With overlapping
• With interruption
The change from pump A to pump B takes place instantly:
3131D42
A
B
The change from pump A to pump B is made with temporal overlapping, e.g. to ensure
a low noise level during changeover. The pump to be deactivated overruns for the
adjusted period of time:
3131D43
A
B
Run priority
Changeover time
Changeover period
No changeover delay
Changeover with
negative delay