Bosch ZWB 28-3 A NG - Connecting the Outdoor Temperature Sensor; Connecting the DHW Tank Temperature Sensor (Only ZBR; Connecting Additional Accessories

Electrical connection
45
Greenstar – 6721822579 (2021/01)
Fig. 45 Schematic of electrical wiring of Bosch room control and boiler
1) Terminal at the boiler reads BUS or BB, both indicating
connection of the 2-wired Bosch BUS system.
7.2.3 Connecting the outdoor temperature sensor
▶ Set up WWSD according to the instruction manual of CRC200.
▶ Punch out plastic insert.
▶ Connect cable of the outdoor temperature sensor according to
Fig. 46.
▶ Insert cable for the outdoor temperature sensor.
▶ Secure the cable on the strain relief.
Fig. 46 Electrical wiring outdoor temperature sensor
7.2.4 Connecting the DHW tank temperature sensor (only ZBR...-
3A)
Wire the DHW tank temperature sensor directly to the appliance
terminals. The sensor is provided with the appliance.
Do not exceed a sensor cable length of 33 feet (10 m).
▶ Punch out plastic insert.
▶ Plug connector into the circuit board.
▶ Insert the cable of the DHW tank temperature sensor.
▶ Secure the cable with the strain relief.
Fig. 47 Electrical connections DHW tank temperature sensor
7.2.5 Connecting additional accessories
▶ For splash protection (IP), always cut the strain relief to match the
diameter of the cable.
Fig. 48 Cut off grommets
▶ Feed cable through strain relief and connect accordingly.
▶ Secure the cable on the strain relief.
Connecting temperature guard TB 1 (external manual reset high
limit or low water cut off (LWCO))
This connection allows the installation of external safety switches.
• External manual reset high limit
• Low water cut-off (LWCO)
• Radiant overheat protection
Fig. 49 Electrical wiring TB 1
When the temperature guard trips, central heating and DHW modes are
interrupted.
CRC200
6 720 811 153-05.1O
BUS
BUS/
BB
1)
6 720 641 933-35.1O
A
F
6 720 641 933-73.1O
6 720 641 933-91.1o
TB1
6 720 641 933-44.1O
B
B
4
2
1
F
A
LS NS
LP
NP
9
8
7
1
2
C
ϑ