LOGO! manual
EWA 4NEB 712 6006-02
98
5.6.1 Demands on the control system for a rainwater
pump
S The water must be available at all times. Whenever necessary, the con-
troller must switch automatically to drinking water.
S When the switch to drinking water takes place, no rainwater must get
into the drinking water system.
S If there is not enough water in the rainwater tank, the pump cannot be
switched on (run-dry protection).
5.6.2 Previous solution
K1 K2
K3
S1
K3
S4 K3
Auxiliary circuit
L1
N
K4
S3 K4
p<
K2
S3 S2
Y1
Pump After-run
time
Run-dry
protection
Pure water
supply
The pump and a solenoid valve are controlled by a pressure switch and 3
float switches in the rainwater tank. The pump must be switched on when
the pressure goes below the minimum permitted. Once the operating pres-
sure is reached, the pump is switched off again after an after-run time of a
few seconds. The after-run time prevents the water pump from constantly
being switched on and off if the water is drawn for any length of time.
Applications
To Next Page
Loading...
