Wilo Stratos 1.25x3-20 Notice De Montage Et De Mise En Service page 13

6.2.2 Differential-pressure control systems
The control systems which can be selected are:
• 'p-v: (Factory default setting) The electronics increase the pump's differential
pressure set point in a straight line between ½ Hs and Hs. The differential
pressure set point Hs increases or decreases in accordance with the required
flow rate (fig. 6).
• 'p-c: The electronics keep the differential pressure generated by the pump at
a constant differential pressure set point Hs over the entire operation range of
the pump (fig. 7).
• 'p-T: The electronics alter the nominal differential pressure set point
dependant on the fluid temperature measured. This control system can only be
adjusted with the IR module. There are two possible settings (fig. 8):
• Positive control: As the system temperature rises, the nominal differential
pressure set point is increased linearly between Hsmin and Hsmax. (setting on
IR module: Hs
Used e.g. with standard boilers with sliding flow temperature.
• Negative control: As the system temperature rises, the nominal differential
pressure set point is decreased linearly between Hsmin and Hsmax (setting on
IR module: Hs
Used e.g. with condensing boilers where a specific maxium return water
temperature must be maintained to achieve as much condensing as possible
to insure maxium boiler effeciency. To do this, the pump must be installed in
the system's return flow section.
6.2.3 Other energy-saving operating modes
• Speed regulation mode operation: The speed of the pump is kept at an
externally set constant speed between minimum and maximum speeds (fig. 9).
The speed regulation mode deactivates the differential pressure control.
• In the "auto" operating mode (factory default setting) the pump is able to
recognize a minimum system heat output requirement due to a sustained drop
in the system temperature and then automitically switch to night setback
mode. If the heat output requirement rises, the pump automatically switches to
standard mode. This setting ensures that the pump's energy consumption is
reduced to a minimum and in most cases is the optimum setting.
CAUTION! Possible damage of the pump!
Setback mode may only be enabled when the system is hydraulically
balanced. Inadequately supplied system parts may otherwise freeze in the
event of frost.
6.2.4 General pump functions
• The pumps are fitted with an electronic overload protection system which
switches the pump off should it become overloaded.
• The control module is equipped with a non-volatile memory for data storage.
What this means is that data is saved, even during long periods of down time.
Once the voltage returns the pump starts operating again with the values set
before the power outage.
Installation and operating instructions Wilo-Stratos /-D/-Z
> Hs ).
max min
< Hs ).
max min
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