Wilo Star-Z Serie Manual De Instalación página 38

6.2 Function of the product
Variable speed control (fig. 8)
The pump types Z(D)20(25)/...-3 have a rotary knob on the
terminal box for manual switching to the three speed stages
[1 – 2 – 3]. The speed in the smallest stage is approx. 40 to 50%
of the maximum speed with a reduction of the current
consumption to 50%.
Special pump features
For a double pump, the two motor impeller units are fitted iden-
tically and are mounted in a common pump housing with inte-
grated switchover valve.
Each pump can run individually, but both pumps can also run at
the same time in parallel operation. The operating modes are
main/standby or parallel/peak-load operation. The individual
units can be configured for different capacities. With the dou-
ble pump, a system can be adapted to individual operating
situations.
It is necessary to connect a corresponding switchgear for
switching-over in order to control the different operating
modes.
7 Installation and electrical connection
DANGER! Risk of fatal injury!
Incorrect installation and improper electrical connections
can be life-threatening.
• The installation and electrical connection may only be carried
out by qualified personnel in accordance with the applicable
regulations!
• Adhere to regulations for accident prevention!
Installation and operating instructions Wilo-Star-Z/-ZD
English
31