On the left side are :
. Green LED : command circuit On.
. Blue LED : automatic mode.
. Red LED : override mode.
. Yellow LED : pump running.
On the middle side :
. The breakdown switch that protects motor.
. The inverter switch for automatic/override modes.
. The On/Off command circuit switch.
On the right side is the tank with :
. The motor supplied by a 24 V DC source.
. A bottom pushbutton that is the low level sensor.
. A top pushbutton that is the high level sensor.
In automatic mode, the high level sensor (full tank) starts the pump until the low level sensor (empty tank) stops it.