Cable Retainer Clamps; Frost Protection - Bosch Worcester Greenstar HIU E Installation And Maintenance Instructions Manual

Installation
5.3.4

Cable retainer clamps

Cable retainer clamps
▶ Each cable entering the control box must be placed
and secured under a cable retainer.
▶ There are three strain reliefs per port, if there is
insufficient room to reinsert the third one it can be
discarded.
Accessing the cable retainer clamps
 Figure 33
▶ Remove the electrical cover [1] by releasing the latches [2] using a
thin bladed screwdriver.
1
2
2
Fig. 33 Removing electrical cover
Cable preparations
NOTICE: Damage to control unit!
Small pieces of wire can cause shorts and damage to
electronics.
▶ When stripping wires always ensure copper strands
do not fall into the control box.
Mains voltage (power cables), example  Figure 34
▶ Ensure the protective conductor is longer than the other wires.
230V
6-8mm
6-8mm
N
L
26-30mm
36-40mm
Fig. 34 Mains voltage (power cables) preparation
Low voltage (signal cables), example  Figure 35
0-30V
6-8mm
26-30mm
Fig. 35 Low voltage (signal cables) preparation
28
Securing the cables
 Figure 36
▶ Unscrew the cable retaining screw [3].
▶ Feed the cable [4] through the cable clamp ensuring there is ample
cable to reach the connectors.
▶ Tighten the cable retaining screw [3] to secure the cable.
3
0-30V
Fig. 36 Cable retainer clamps
0-30V
[ ] Low voltage (signal cables) connections side
230V
[ ] Mains voltage (power cables) connections side
2
▶ Replace the electrical cover, ensuring all latches are fitted correctly.
5.4

Frost protection

The frost protection function within the unit is split into two categories,
that are system frost protection and unit frost protection:
• System frost protection (only if a Sense II is permanently installed).
– The central heating circulation pump is activated as soon as the
compatible EMS BUS controller/outdoor sensor sends a frost
protection signal, which can be triggered by a low room
temperature or a low outside temperature.
• Internal frost protection.
– The central heating flow sensor detects a temperature below
8 °C, the central heating circulation pump is activated.
– Additionally if the central heating flow sensor detects a
temperature below 5 °C, the central heating control valve opens.
3
4
230V
6 720 808 928 (2017/06)
4