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Building Technologies
Boiler Sequence Controller RMK770
CE1P3132en
HVAC Products
5 General functions, fundamentals
01.03.2005
The changeover from pump A to pump B is made after a certain pause, e.g. to prevent
voltage peaks or excessive water pressures.
31
31
D
44
A
B
Depending on the changeover priority, the pump kick will act as follows:
Impact of pump kick
Operating state of the
pumps
With automatic changeover
With fixed assignment
Both pumps do not
run (summer opera-
tion)
Kick first acts on the pump that
was in operation last
Kick first acts on the re-
serve pump and then on
the working pump
1 of the 2 pumps runs Not applicable
Kick only acts on the re-
serve pump
Delayed changeover also acts with the pump kick.
5.8.2
Overload message and supervision of flow
With the pump fault inputs and flow input – as with every digital input – the normal posi-
tion can be parameterized (
… > Settings > Inputs > Terminal … > Normal position
).
If a twin pump is used and one of the pumps becomes faulty, changeover to the other
pump will take place.
In any case, a fault status message will be delivered. This message must be acknowl-
edged, but no reset is required.
If both inputs signal a fault, a reset must be made.
Flow supervision only becomes active 60 seconds after the pump is switched on.
The behavior in the event of a pump fault depends on the type of function block.
If a twin pump is used, the fault behavior of the relevant block becomes active only if
both pumps fail.
If the boiler pump becomes faulty, the boiler is considered faulty, and a backup boiler
will be released.
If the main pump becomes faulty, the entire boiler sequence is considered faulty, and
all boilers will be shut down.
If a heating circuit pump or system pump becomes faulty (primary controller), the plant
continues to operate.
Number Text
Description
2401
[K1 pump] overload
Boiler pump, boiler 1, fault overload
2421
[K1 pump B] overload Boiler pump B, boiler 1, fault overload
2411
[K1 pump] no flow
Boiler pump, boiler 1, flow fault
2431
[K1 pump B] no flow
Boiler pump B, boiler 1, flow fault
2441
[Boiler 1 pump] fault
Boiler pump, boiler 1, fault
For the complete list of fault status messages, refer to chapter 14 “Fault tracing sup-
port”.
Changeover with
positive delay
Pump kick
Fault status messages,
using the example of the
boiler twin pump