Bosch ZWB28-3A - Connecting the LWCO Device

Making the electrical connections | 57
6 720 643 068 (2011/06)Copyright (optional information)
6.4 Connecting the LWCO device
B Punch a hole (maximum diameter 3/16" (5 mm))
through the fan cable grommet (steps 1 – 3) and run
the LWCO cable through it.
Fig. 51 Punch a hole in fan cable grommet for LWCO cable
B Install a 24VAC 20VA transformer near the boiler.
B Follow LWCO manufacturer’s instructions.
B Connect the lead labeled BOILER GROUND (green) to
pin 2 (center, Æ Fig. 49 [2]) of the white plug in the
boiler junction box.
B Connect the leads labeled 24V HOT (red) and 24V
COMMON (white) to the external 24VAC transformer.
B Connect the leads labeled SWITCH CONTACT (yellow)
to the TB1 temperature guard (Æ Fig 40, page 54) on
the Heatronic.
Fig. 52 Wires of a LWCO device with LWCO adapter
1 LWCO device (Hydrolevel Safgard 1100)
2 BOILER GROUND (green)
3 SWITCH CONTACT (yellow)
4 SWITCH CONTACT (yellow)
5 24V HOT (red)
6 24V COMMON (white)
NOTICE: System damage or malfunction!
B Ensure the air box remains air-tight when
routing the LWCO cable to the outside.
B Do not route the LWCO cable through the
ignition cable grommet as appliance
malfunction may occur.
6 720 641 933-87.1O
Ø ≤ 3/16"
(~ 5 mm)
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2
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1
6 720 641 933-67.1O