3
VRT 50 Room Thermostat Operating and Installation Manual
7
Safety instructions and regulations
The device must be installed by an approved qualified
servicing company, which is responsible for adhering to
the existing standards and regulations.
We accept no liability for any damage caused by failure
to observe these instructions.
All wiring must be in accordance with Building Regula-
tions Part P and BS 7671 (IEE Wiring Regulations), and
must be carried out by a suitably qualified person.
Use standard commercial cables for wiring.
- Minimum cross-section of the wires: 0.75 mm
2
Do not exceed the following maximum wire lengths:
- Bus lines: 300 m
230 V connection lines and bus lines must be laid sepa-
rately if they are longer than 10 m.
The controller may only be installed in dry rooms.
8 Installation
8.1 Place
of
installation
m
5.
1
Fig. 8.1 Selecting the place of installation
8.2
Mounting the room thermostat
2
3
1
Fig. 8.2 Opening the (programmable) room thermostat
The thermostat is connected to the boiler with a two-
wire bus cable (eBUS).
• Open the (programmable) room thermostat by undo-
ing the snap-fit on the bottom (
2
), flapping the cover
of the housing (
1
) upwards and removing it from the
base of the housing (
3
).
4
3
5
6
Fig. 8.3 Mounting the (programmable) room thermostat
• Drill two holes (
5
) of 6 mm diameter and insert the
supplied wall plugs.
• Lay the connection cable through the duct (
6
).
• Attach the housing base (
3
) to the wall with the two
screws provided.
• Connect the connection cable as described in Sec-
tion 10.
• Close the housing by placing the cover of the housing
with the top edge in the snap-fit (
4
) of the housing
base, flapping it downwards and pressing it until you
hear it snap into place in the housing base.
9 Electrical
installation
The electrical connection may be carried out only by an
approved qualified servicing company.
9.1
Connecting the room thermostat
The thermostat communicates with the boiler via a
two-wire bus cable (eBUS). All eBUS connector plugs are
designed to allow you to wire at least 2 x 0.75 mm
2
(rec-
ommended) per connection terminal. This means that
the wires can be swapped without impairing communica-
tion (see Fig. 9.1). Also follow the instructions for the
boiler.
h
Note!
- A bridge must be inserted at the boiler be-
tween terminals 3 and 4 when operating the
VRT 50.
- No other eBUS controllers can be connected
to the boiler in addition to the VRT 50.
