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13.4.5. Pump kick
13.4.6. Winter- / summertime changeover
13.4.7. Gain of locking signal
13.4.7.1. Fundamentals
13.4.7.2. Uncritical locking signals
13.4.7.3. Critical locking signals
CE1P2522E / 30.03.2000
48/68
To prevent pump seizure during longer off periods (e.g. in the summer), it is possible to
activate periodic pump runs:
0 = no periodic pump run
1 = periodic pump run activated
Periodic pump run lasts 30 seconds and takes place once a week, every Friday morning
at 10:00.
The change from wintertime to summertime, and vice versa, takes place automatically.
If international regulations change, the dates need to be reentered.
The entry then to be made is the earliest possible changeover date. The weekday on
which changeover occurs is always a Sunday.
Example:
If the start of summertime is given as "the last Sunday in March", the earliest possible
changeover date is March 25. The date to be entered then is 25.03.
If no summer- / wintertime changeover is required, the two dates are to be set such that
they coincide.
The functions "Maintained boiler return temperature", "Protective boiler startup" and
"D.h.w. priority" use locking signals that are sent to the heat exchangers and loads. With
the heat exchanger and load controllers, it is possible to set on operating line 173 (Am-
plification of locking signal) to what degree they shall respond to a locking signal. This
gain of the locking signal is adjustable from 0 % to 200 %.
Setting Response
0 %
Locking signal will be ignored
100 % Locking signal will be adopted 1:1
200 % Locking signal will be doubled
There are two types of locking signals:
•
Uncritical locking signals
•
Critical locking signals
The response of the loads depends on the kind of load.
Uncritical locking signals are generated in connection with d.h.w. priority (absolute and
shifting) and only act on the heating circuits.
The response of the heating circuit depends on the type of heating circuit:
•
Heating circuit with mixing valve:
In the heating circuit, the flow temperature setpoint will be reduced in function of the
set locking signal gain. The mixing valves close.
•
Heating circuit with pump:
In case of a defined value of the uncritical locking signal, the heating circuit pump will
be deactivated, independent of the set locking signal gain. In plants with chengeover
valve, the valve assumes the "Heating circuit" position.
Critical locking signals are generated by the boiler temperature controller during protec-
tive boiler startup and during minimum limitation of the boiler return temperature. If the
boiler temperature controller is located in segment 0, the critical locking signal will be
sent to all loads and heat exchangers in the bus network and – if present – to its own
Basic Documentation RVL470
Function block "Service functions and general settings"
Siemens Building Technologies
Landis & Staefa Division
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