Rizzoli STP SF Série Manuel D'utilisation page 131

VARIABLE PRESSURE DIFFERENCE (ΔP-C): 1,4,7
The differential-pressure setpoint H is kept con-
stant over the permitted volume flow range at the
set
differential-pressure setpoint up to the maximum
pump curve (picture 29).
The operating knob is set on the left of the middle
position. Wilo recommends this control mode for
under-floor eating circuits or older heating sys-
tems with large sized pipes as well as for all appli-
cations with no changeable pipe system curve, e.g.
boiler charge pumps.
STEADY SPEED I, II, III
The pump is operating continuously with the pre-
set speed (picture 30).
The operating knob for a fixed constant speed
is set on the right of the middle position. In this
operating mode the pump is not self regulating
its speed. The pump is operating constantly with
a fixed speed.
NOTE: All settings are retained if the mains supply is interrupted.
Picture 29 - Curve trend variable pressure difference
mode.
Picture 31. Curve trends steady speed mode
129