Kessel Comfort PLUS Original Operation Manual page 49

Duo float switch (non-ATEX)
Connect the ends of the float switch cables as shown in"Fig. [20]".
010-700_01
Alarm
On2
On1
O
A = Pump switched off (Off)
B = Switch pump 1 on (On1)
Fig. [20]
Installation and operating manual
C = Switch pump 2 on (On2)
D = Alarm
Alarm
On2
On1
O
49