Wilo W-CTRL-CC Série Notice De Montage Et De Mise En Service page 48

English
If the power requirement cannot be met by this
pump, the control system switches on a peak-load
pump and, if the requirement increases further,
other peak-load pumps (start level:
load pumps run at constant speed, the speed of
the base-load pump is regulated to the setpoint
¢
in each case.
If the requirement drops until the controlling
pump is working in its lower performance range
and no peak-load pump is required any longer in
order to meet the requirement then the peak-load
pump switches off (stop level:
pump switches off independently via the zero-
flow cut-off (stop level:
again below the start level
restarts.
The parameter settings required for switching
on and off the peak-load pump (switching level
Ÿ ¡
/
; delay times) can be set in menu 4.3.3.2.
A selection can be made between the same
switch-off level for all pumps and pump-specific
switch-off level. The system suggests pump-spe-
cific switch-off levels. For this it is necessary to
enter Q and H
nom 0
To avoid pressure peaks when switching on or
pressure troughs when switching off a peak-load
pump, the speed of the base-load pump can
be raised or reduced during these switching
operations. Corresponding frequency settings
of these so-called peak filters can be undertaken
in 4.3.5.1 – page 2.
Normal operation of switchgear without
frequency converter – CC version (see Fig. 4)
The controlled variable is taken from comparison
of the setpoint/actual value for switchgears with-
out a frequency converter (mains operation) or
with a faulty frequency converter. Because there
is no possibility of load-dependent speed adapta-
tion of the base-load pump, the system works as
a two-point controller between
Switching on and off the peak-load pump is done
in the manner described above.
For switching off the base-load pump, a separate
switching threshold
42
Ÿ
). The peak-
¡
). The base-load
ž
). If the pressure sinks
œ
, then the pump
in menu 1.2.
œ ž Ÿ ¡
/ /
or .
ž
can be set in menu 4.3.3.1.
Normal operation of switchgear in the CCe version
(see Fig. 5)
A selection can be made between 2 operating
modes for switchgear in the CCe version. The set-
ting parameter described for switchgear CC...FC is
used each time for this.
The cascade mode corresponds in its operation to
the normal operation of switchgear in the CC...FC
version (see Fig. 3), whereby the peak-load pumps
are activated with maximum speed.
In Vario mode (see Fig. 5), one pump starts as
a load-dependent speed-controlled base-load
pump (Fig. 5a). If the required power requirement
can no longer be met by this pump at maximum
speed, another pump starts and takes over the
speed control. The previous base-load pump con-
tinues at max. speed as a peak-load pump
(Fig. 5b). This procedure is repeated at increasing
load until the maximum number of pumps is
reached (here: 3 pumps – see Fig. 5c).
If the requirement sinks, the controlling pump will
be switched off when the minimum speed is
reached and a former peak-load pump takes over
control.
Zero-flow cut-off
When only one pump is operating in the lower fre-
quency range and with a constant pressure, a
zero-flow test is performed cyclically (settable) by
settable increases of the setpoint for a time that
can be set (menu 4.3.3.5). If the pressure does not
drop again after the higher setpoint is withdrawn,
this means there is zero flow and the base-load
pump is switched off after the follow-up time has
expired (menu 4.3.3.1).
For operation without frequency converter, the
base-load pump is switched off after reaching the
2nd switch-off level (see above) and after expiry
of the follow-up time.
If the pressure sinks below the switch-on level of
the base-load pump, this switches on again.
Pump exchange
Various mechanisms of pump exchange are
applied optionally in order to ensure that the loads
on all pumps are distributed as evenly as possible
and to balance the running times of the pumps.
The corresponding settings can be made in
menu 4.3.4.2.
If pump exchange dependent on the operating
hours is selected, the system specifies the base-
load pump (service life optimisation) by means of
the operating hours counter and the pump diag-
nostics (faults, release). The time to be set for this
exchange mechanism expresses the maximum
permitted service time difference.
WILO SE 11/2018