Wilo SC-Booster SC Notice De Montage Et De Mise En Service page 50

Normal operation of SC switchgear without
frequency converter (see Fig. 3)
An electronic signal transmitter (measurement
range to be set in menu 5.2.1.0) supplies the con-
trol variable actual value as a 4...20 mA current
signal. There is no possibility for load-sensitive
speed adaptation of the base-load pump, as a
result of which the system works as a two-point
controller and keeps the pressure in the range
between the activation and deactivation thresh-
olds (menus 1.2.2.1 to 1.2.2.8). These must be
set in relation to the reference setpoint (menu
1.2.1.1).
If there is no "external off" signal and no fault, the
base-load pump starts when its activation thresh-
old is undershot
not be met by this pump, the control system
switches on a peak-load pump and, if the require-
ment increases further, another peak-load pump
(activation threshold:
per pump; menu 1.2.2.3/5/7).
If the requirement drops until no peak-load pump
is required any longer in order to meet the require-
ment then the peak-load pump switches off
(deactivation threshold:
ble per pump; menu 1.2.2.4/6/8).
If no peak-load pump is active any longer, the
base-load pump switches off when the deactiva-
tion threshold is undershot (
after the delay time has expired (menu 1.2.5.1).
Delay times can be set in the menus 1.2.5.2 and
1.2.5.3 for activation and deactivation of the
peak-load pump.
Normal operation of SCe switchgear (see Fig. 4)
An electronic signal transmitter (measurement
range to be set in menu 5.2.1.0) supplies the con-
trol variable actual value as a 4...20 mA current
signal. Then the controller maintains the system
pressure constant by means of the comparison of
the setpoint/actual value (for setting of the refer-
›
ence setpoint
"external off" signal and no fault, the base-load
pump with load-sensitive speed control (Fig. 4a)
starts when its activation threshold is undershot
œ
(menu 1.2.2.1). If the power requirement can
no longer be met by this pump at the speed that
can be set in menu 1.2.3.1, another pump starts
when the reference setpoint is undershot
takes over the speed control (Fig. 4b). The previ-
ous base-load pump continues to run at max.
speed as a peak-load pump. This procedure is
repeated at increasing load until the maximum
number of pumps is reached (here: 3 pumps – see
Fig. 4c).
If the requirement drops then the controlling
pump is switched off when the speed that can be
set in menu 1.2.3.2 is reached, and the reference
setpoint is exceeded at the same time; then, a
former peak-load pump takes over control.
If no peak-load pump is active any longer, the
base-load pump switches off when the deactiva-
Installation and operating instructions Wilo-Control SC-Booster (SC, SC-FC, SCe)
œ
. If the power requirement can-
Ÿ
; individually adjustable
¡
; individually adjusta-
ž
menu 1.2.2.2) and
see menu 1.2.1.1). If there is no
›
tion threshold is undershot (
after the delay time has expired (menu 1.2.5.1), if
necessary following a zero-flow test.
Delay times can be set in the menus 1.2.5.2 and
1.2.5.3 for activation and deactivation of the
peak-load pump.
Zero-flow test (only SC-FC and SCe versions)
When only one pump is operating in the lower fre-
quency range and with a constant pressure, a
zero-flow test is performed cyclically by briefly
increasing the setpoint to a value above the deac-
tivation threshold of the base-load pump (menu
1.2.2.2). 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
1.2.5.1).
The parameters of the zero-flow test are preset at
the factory, and can only be changed by Wilo cus-
tomer service.
Pump cycling
Various mechanisms of pump cycling 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 base-load pump is cycled on each require-
ment (after deactivation of all pumps).
Furthermore, a cycling of the base-load pump can
also be activated (menu 5.6.1.0). The running time
between 2 cycling procedures can be set in menu
5.6.2.0.
Standby pump
One pump can be defined as the standby pump.
Activating this operating mode means that this
pump is not activated in normal mode. It is only
switched on if a pump fails due to a fault. How-
ever, the standby pump is subject to standstill
monitoring and is included in the test run. Service
life optimisation ensures that every pump
becomes a standby pump once.
This function is preset at the factory, and can only
be changed by Wilo customer service.
and
Pump test run
A cyclic test run of the pump can be activated in
order to avoid lengthy standstill times (menu
5.7.1.0). The time between 2 test runs can be
defined in menu 5.7.2.0 for this purpose. In the
SCe and SC-FC versions, the speed of the pump
can be set (during the test run) (menu 5.7.3.0).
A test run only takes place at when the system is
at a standstill (after zero-flow cut-off), and does
not happen when the switchgear is in "external
off" status.
English
ž
menu 1.2.2.2) and
43