Installation
Connecting the temperature sensors and the bus
Terminal Description Type (recomm.)
15 and 16 System device bus*, 
connections for room 
panel** / remote control** / 
(relay module)
ECA 60 / 62
ECA 61 / 63
17 and 16 S1 Outdoor temperature
sensor 
ESMT
18 and 16 S2 Flow temperature sensor **, 
circuit I
ESM-11 / ESMC / 
ESMU
19 and 16 S3 Return temperature sensor, 
circuit I
ESM-11 / ESMC / 
ESMU
20 and 16 S4 Flow temperature sensor, 
circuit II
ESM-11 / ESMC / 
ESMU
21 and 16 S5 Return temperature sensor, 
circuit II or
lower DHW tank 
temperature sensor, circuit II
ESM-11 / ESMC / 
ESMU
ESMB
22 and 16 S6 Upper DHW tank 
temperature sensor***
ESMB / ESMU
*  The system device bus / room panel / remote control is only active
  when the outdoor temperature sensor is connected.
**  Either room temperature sensor or room panel / remote control
***  If only one DHW tank temperature sensor is used, it must be connected
  to terminal 22
Establish the jumper from 16 to common terminal.
Wire cross section for sensor connections: 
  Min. 0.4 mm
2
Total cable length:   Max. 125 m (all sensors incl. system device 
bus)
Cable lengths of more than 125 m may cause noise sensibility 
(EMC).
Connecting and placing the 
temperature sensors
14a