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Siemens
Heating and D.h.w. Controller RVL481
CE1P2541en
Building Technologies
25 Function block "Service functions and general settings"
20.05.2008
D.h.w. discharging protection has priority over pump overrun.
In interconnected plants, the time set also affects the forced signals that a boiler can
deliver to ensure overtemperature protection.
For detailed information, refer to section “12.4.5 Protection against boiler overtempera-
tures”.
25.4.5 Pump
kick
To prevent pump seizing during longer off periods (e.g. in the summer), it is possible to
activate periodic pump runs: The input is either “0” or “1”:
0 = no periodic pump kick
1 = periodic pump kick activated
If the pump kick is activated, all pumps run for 30 seconds, one after the other, every
Friday morning at 10:00, independent of all other functions and settings.
With plant types 2–1, 2–2, and 3–1, pump Q1 is kicked only when, at the same time,
charging pump Q3 does not operate.
25.4.6 Winter- / summertime changeover
The change from wintertime to summertime, and vice versa, is made automatically. If
international regulations change, the dates need to be re-entered. The entry to be
made is the earliest possible changeover date. The weekday on which changeover
occurs is always a Sunday.
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 on operating line 176 is then
25.03.
If no summer- / wintertime changeover is required, the two dates are to be set such that
they coincide.
25.4.7 Gain of locking signal
The functions "Maintained boiler return temperature", "Protective boiler start-up" and
"D.h.w. priority" use locking signals that are sent to the heat exchangers and loads.
With the heat convector and load controllers, it is possible to set on operating line 173
(amplification 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 2 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 the 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 as a function of the
set locking signal gain. The mixing valve closes.
•
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 changeover
valve, the valve assumes the "D.h.w.” position
Example
Fundamentals
Uncritical locking
signals
